]> git.madduck.net Git - etc/vim.git/blobdiff - tests/test_black.py

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

Run pyupgrade on blib2to3 and src (#3771)
[etc/vim.git] / tests / test_black.py
index 7389da9417fbfb8a03df7d1dbf49c59a8678616c..dd21d0a7ae6a00d7614e3c4a995ce96d9f7c44c0 100644 (file)
@@ -1,55 +1,80 @@
 #!/usr/bin/env python3
+
 import asyncio
-from concurrent.futures import ThreadPoolExecutor
-from contextlib import contextmanager
-from functools import partial
-from io import StringIO
+import inspect
+import io
+import logging
+import multiprocessing
 import os
-from pathlib import Path
+import re
 import sys
-from tempfile import TemporaryDirectory
-from typing import Any, List, Tuple, Iterator
+import types
 import unittest
-from unittest.mock import patch
-import re
-
+from concurrent.futures import ThreadPoolExecutor
+from contextlib import contextmanager, redirect_stderr
+from dataclasses import replace
+from io import BytesIO
+from pathlib import Path
+from platform import system
+from tempfile import TemporaryDirectory
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Iterator,
+    List,
+    Optional,
+    Sequence,
+    Type,
+    TypeVar,
+    Union,
+)
+from unittest.mock import MagicMock, patch
+
+import click
+import pytest
 from click import unstyle
 from click.testing import CliRunner
+from pathspec import PathSpec
 
 import black
+import black.files
+from black import Feature, TargetVersion
+from black import re_compile_maybe_verbose as compile_pattern
+from black.cache import get_cache_dir, get_cache_file
+from black.debug import DebugVisitor
+from black.output import color_diff, diff
+from black.report import Report
+
+# Import other test classes
+from tests.util import (
+    DATA_DIR,
+    DEFAULT_MODE,
+    DETERMINISTIC_HEADER,
+    PROJECT_ROOT,
+    PY36_VERSIONS,
+    THIS_DIR,
+    BlackBaseTestCase,
+    assert_format,
+    change_directory,
+    dump_to_stderr,
+    ff,
+    fs,
+    get_case_path,
+    read_data,
+    read_data_from_file,
+)
 
-ll = 88
-ff = partial(black.format_file_in_place, line_length=ll, fast=True)
-fs = partial(black.format_str, line_length=ll)
 THIS_FILE = Path(__file__)
-THIS_DIR = THIS_FILE.parent
-EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
-
-
-def dump_to_stderr(*output: str) -> str:
-    return "\n" + "\n".join(output) + "\n"
+EMPTY_CONFIG = THIS_DIR / "data" / "empty_pyproject.toml"
+PY36_ARGS = [f"--target-version={version.name.lower()}" for version in PY36_VERSIONS]
+DEFAULT_EXCLUDE = black.re_compile_maybe_verbose(black.const.DEFAULT_EXCLUDES)
+DEFAULT_INCLUDE = black.re_compile_maybe_verbose(black.const.DEFAULT_INCLUDES)
+T = TypeVar("T")
+R = TypeVar("R")
 
-
-def read_data(name: str) -> Tuple[str, str]:
-    """read_data('test_name') -> 'input', 'output'"""
-    if not name.endswith((".py", ".pyi", ".out", ".diff")):
-        name += ".py"
-    _input: List[str] = []
-    _output: List[str] = []
-    with open(THIS_DIR / name, "r", encoding="utf8") as test:
-        lines = test.readlines()
-    result = _input
-    for line in lines:
-        line = line.replace(EMPTY_LINE, "")
-        if line.rstrip() == "# output":
-            result = _output
-            continue
-
-        result.append(line)
-    if _input and not _output:
-        # If there's no output marker, treat the entire file as already pre-formatted.
-        _output = _input[:]
-    return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
+# Match the time output in a diff, but nothing else
+DIFF_TIME = re.compile(r"\t[\d\-:+\. ]+")
 
 
 @contextmanager
@@ -58,328 +83,455 @@ def cache_dir(exists: bool = True) -> Iterator[Path]:
         cache_dir = Path(workspace)
         if not exists:
             cache_dir = cache_dir / "new"
-        with patch("black.CACHE_DIR", cache_dir):
+        with patch("black.cache.CACHE_DIR", cache_dir):
             yield cache_dir
 
 
 @contextmanager
-def event_loop(close: bool) -> Iterator[None]:
+def event_loop() -> Iterator[None]:
     policy = asyncio.get_event_loop_policy()
-    old_loop = policy.get_event_loop()
     loop = policy.new_event_loop()
     asyncio.set_event_loop(loop)
     try:
         yield
 
     finally:
-        policy.set_event_loop(old_loop)
-        if close:
-            loop.close()
+        loop.close()
 
 
-class BlackTestCase(unittest.TestCase):
-    maxDiff = None
+class FakeContext(click.Context):
+    """A fake click Context for when calling functions that need it."""
 
-    def assertFormatEqual(self, expected: str, actual: str) -> None:
-        if actual != expected and not os.environ.get("SKIP_AST_PRINT"):
-            bdv: black.DebugVisitor[Any]
-            black.out("Expected tree:", fg="green")
-            try:
-                exp_node = black.lib2to3_parse(expected)
-                bdv = black.DebugVisitor()
-                list(bdv.visit(exp_node))
-            except Exception as ve:
-                black.err(str(ve))
-            black.out("Actual tree:", fg="red")
-            try:
-                exp_node = black.lib2to3_parse(actual)
-                bdv = black.DebugVisitor()
-                list(bdv.visit(exp_node))
-            except Exception as ve:
-                black.err(str(ve))
-        self.assertEqual(expected, actual)
+    def __init__(self) -> None:
+        self.default_map: Dict[str, Any] = {}
+        self.params: Dict[str, Any] = {}
+        # Dummy root, since most of the tests don't care about it
+        self.obj: Dict[str, Any] = {"root": PROJECT_ROOT}
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_self(self) -> None:
-        source, expected = read_data("test_black")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-        self.assertFalse(ff(THIS_FILE))
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_black(self) -> None:
-        source, expected = read_data("../black")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-        self.assertFalse(ff(THIS_DIR / ".." / "black.py"))
+class FakeParameter(click.Parameter):
+    """A fake click Parameter for when calling functions that need it."""
 
-    def test_piping(self) -> None:
-        source, expected = read_data("../black")
-        hold_stdin, hold_stdout = sys.stdin, sys.stdout
+    def __init__(self) -> None:
+        pass
+
+
+class BlackRunner(CliRunner):
+    """Make sure STDOUT and STDERR are kept separate when testing Black via its CLI."""
+
+    def __init__(self) -> None:
+        super().__init__(mix_stderr=False)
+
+
+def invokeBlack(
+    args: List[str], exit_code: int = 0, ignore_config: bool = True
+) -> None:
+    runner = BlackRunner()
+    if ignore_config:
+        args = ["--verbose", "--config", str(THIS_DIR / "empty.toml"), *args]
+    result = runner.invoke(black.main, args, catch_exceptions=False)
+    assert result.stdout_bytes is not None
+    assert result.stderr_bytes is not None
+    msg = (
+        f"Failed with args: {args}\n"
+        f"stdout: {result.stdout_bytes.decode()!r}\n"
+        f"stderr: {result.stderr_bytes.decode()!r}\n"
+        f"exception: {result.exception}"
+    )
+    assert result.exit_code == exit_code, msg
+
+
+class BlackTestCase(BlackBaseTestCase):
+    invokeBlack = staticmethod(invokeBlack)
+
+    def test_empty_ff(self) -> None:
+        expected = ""
+        tmp_file = Path(black.dump_to_file())
         try:
-            sys.stdin, sys.stdout = StringIO(source), StringIO()
-            sys.stdin.name = "<stdin>"
-            black.format_stdin_to_stdout(
-                line_length=ll, fast=True, write_back=black.WriteBack.YES
-            )
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
+            self.assertFalse(ff(tmp_file, write_back=black.WriteBack.YES))
+            actual = tmp_file.read_text(encoding="utf-8")
         finally:
-            sys.stdin, sys.stdout = hold_stdin, hold_stdout
+            os.unlink(tmp_file)
         self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_one_empty_line(self) -> None:
+        mode = black.Mode(preview=True)
+        for nl in ["\n", "\r\n"]:
+            source = expected = nl
+            assert_format(source, expected, mode=mode)
+
+    def test_one_empty_line_ff(self) -> None:
+        mode = black.Mode(preview=True)
+        for nl in ["\n", "\r\n"]:
+            expected = nl
+            tmp_file = Path(black.dump_to_file(nl))
+            if system() == "Windows":
+                # Writing files in text mode automatically uses the system newline,
+                # but in this case we don't want this for testing reasons. See:
+                # https://github.com/psf/black/pull/3348
+                with open(tmp_file, "wb") as f:
+                    f.write(nl.encode("utf-8"))
+            try:
+                self.assertFalse(
+                    ff(tmp_file, mode=mode, write_back=black.WriteBack.YES)
+                )
+                with open(tmp_file, "rb") as f:
+                    actual = f.read().decode("utf-8")
+            finally:
+                os.unlink(tmp_file)
+            self.assertFormatEqual(expected, actual)
+
+    def test_experimental_string_processing_warns(self) -> None:
+        self.assertWarns(
+            black.mode.Deprecated, black.Mode, experimental_string_processing=True
+        )
+
+    def test_piping(self) -> None:
+        source, expected = read_data_from_file(PROJECT_ROOT / "src/black/__init__.py")
+        result = BlackRunner().invoke(
+            black.main,
+            [
+                "-",
+                "--fast",
+                f"--line-length={black.DEFAULT_LINE_LENGTH}",
+                f"--config={EMPTY_CONFIG}",
+            ],
+            input=BytesIO(source.encode("utf-8")),
+        )
+        self.assertEqual(result.exit_code, 0)
+        self.assertFormatEqual(expected, result.output)
+        if source != result.output:
+            black.assert_equivalent(source, result.output)
+            black.assert_stable(source, result.output, DEFAULT_MODE)
 
     def test_piping_diff(self) -> None:
-        source, _ = read_data("expression.py")
-        expected, _ = read_data("expression.diff")
-        hold_stdin, hold_stdout = sys.stdin, sys.stdout
-        try:
-            sys.stdin, sys.stdout = StringIO(source), StringIO()
-            sys.stdin.name = "<stdin>"
-            black.format_stdin_to_stdout(
-                line_length=ll, fast=True, write_back=black.WriteBack.DIFF
-            )
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
-        finally:
-            sys.stdin, sys.stdout = hold_stdin, hold_stdout
+        diff_header = re.compile(
+            r"(STDIN|STDOUT)\t\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d\.\d\d\d\d\d\d"
+            r"\+\d\d:\d\d"
+        )
+        source, _ = read_data("simple_cases", "expression.py")
+        expected, _ = read_data("simple_cases", "expression.diff")
+        args = [
+            "-",
+            "--fast",
+            f"--line-length={black.DEFAULT_LINE_LENGTH}",
+            "--diff",
+            f"--config={EMPTY_CONFIG}",
+        ]
+        result = BlackRunner().invoke(
+            black.main, args, input=BytesIO(source.encode("utf-8"))
+        )
+        self.assertEqual(result.exit_code, 0)
+        actual = diff_header.sub(DETERMINISTIC_HEADER, result.output)
         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
         self.assertEqual(expected, actual)
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_setup(self) -> None:
-        source, expected = read_data("../setup")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-        self.assertFalse(ff(THIS_DIR / ".." / "setup.py"))
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_function(self) -> None:
-        source, expected = read_data("function")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_function2(self) -> None:
-        source, expected = read_data("function2")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+    def test_piping_diff_with_color(self) -> None:
+        source, _ = read_data("simple_cases", "expression.py")
+        args = [
+            "-",
+            "--fast",
+            f"--line-length={black.DEFAULT_LINE_LENGTH}",
+            "--diff",
+            "--color",
+            f"--config={EMPTY_CONFIG}",
+        ]
+        result = BlackRunner().invoke(
+            black.main, args, input=BytesIO(source.encode("utf-8"))
+        )
+        actual = result.output
+        # Again, the contents are checked in a different test, so only look for colors.
+        self.assertIn("\033[1m", actual)
+        self.assertIn("\033[36m", actual)
+        self.assertIn("\033[32m", actual)
+        self.assertIn("\033[31m", actual)
+        self.assertIn("\033[0m", actual)
 
     @patch("black.dump_to_file", dump_to_stderr)
-    def test_expression(self) -> None:
-        source, expected = read_data("expression")
-        actual = fs(source)
+    def _test_wip(self) -> None:
+        source, expected = read_data("miscellaneous", "wip")
+        sys.settrace(tracefunc)
+        mode = replace(
+            DEFAULT_MODE,
+            experimental_string_processing=False,
+            target_versions={black.TargetVersion.PY38},
+        )
+        actual = fs(source, mode=mode)
+        sys.settrace(None)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        black.assert_stable(source, actual, black.FileMode())
+
+    def test_pep_572_version_detection(self) -> None:
+        source, _ = read_data("py_38", "pep_572")
+        root = black.lib2to3_parse(source)
+        features = black.get_features_used(root)
+        self.assertIn(black.Feature.ASSIGNMENT_EXPRESSIONS, features)
+        versions = black.detect_target_versions(root)
+        self.assertIn(black.TargetVersion.PY38, versions)
+
+    def test_pep_695_version_detection(self) -> None:
+        for file in ("type_aliases", "type_params"):
+            source, _ = read_data("py_312", file)
+            root = black.lib2to3_parse(source)
+            features = black.get_features_used(root)
+            self.assertIn(black.Feature.TYPE_PARAMS, features)
+            versions = black.detect_target_versions(root)
+            self.assertIn(black.TargetVersion.PY312, versions)
 
     def test_expression_ff(self) -> None:
-        source, expected = read_data("expression")
+        source, expected = read_data("simple_cases", "expression.py")
         tmp_file = Path(black.dump_to_file(source))
         try:
             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.YES))
-            with open(tmp_file, encoding="utf8") as f:
-                actual = f.read()
+            actual = tmp_file.read_text(encoding="utf-8")
         finally:
             os.unlink(tmp_file)
         self.assertFormatEqual(expected, actual)
         with patch("black.dump_to_file", dump_to_stderr):
             black.assert_equivalent(source, actual)
-            black.assert_stable(source, actual, line_length=ll)
+            black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_expression_diff(self) -> None:
-        source, _ = read_data("expression.py")
-        expected, _ = read_data("expression.diff")
+        source, _ = read_data("simple_cases", "expression.py")
+        expected, _ = read_data("simple_cases", "expression.diff")
         tmp_file = Path(black.dump_to_file(source))
-        hold_stdout = sys.stdout
+        diff_header = re.compile(
+            rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
+        )
         try:
-            sys.stdout = StringIO()
-            self.assertTrue(ff(tmp_file, write_back=black.WriteBack.DIFF))
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
-            actual = actual.replace(str(tmp_file), "<stdin>")
+            result = BlackRunner().invoke(
+                black.main, ["--diff", str(tmp_file), f"--config={EMPTY_CONFIG}"]
+            )
+            self.assertEqual(result.exit_code, 0)
         finally:
-            sys.stdout = hold_stdout
             os.unlink(tmp_file)
-        actual = actual.rstrip() + "\n"  # the diff output has a trailing space
+        actual = result.output
+        actual = diff_header.sub(DETERMINISTIC_HEADER, actual)
         if expected != actual:
             dump = black.dump_to_file(actual)
             msg = (
-                f"Expected diff isn't equal to the actual. If you made changes "
-                f"to expression.py and this is an anticipated difference, "
-                f"overwrite tests/expression.diff with {dump}"
+                "Expected diff isn't equal to the actual. If you made changes to"
+                " expression.py and this is an anticipated difference, overwrite"
+                f" tests/data/expression.diff with {dump}"
             )
             self.assertEqual(expected, actual, msg)
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_fstring(self) -> None:
-        source, expected = read_data("fstring")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+    def test_expression_diff_with_color(self) -> None:
+        source, _ = read_data("simple_cases", "expression.py")
+        expected, _ = read_data("simple_cases", "expression.diff")
+        tmp_file = Path(black.dump_to_file(source))
+        try:
+            result = BlackRunner().invoke(
+                black.main,
+                ["--diff", "--color", str(tmp_file), f"--config={EMPTY_CONFIG}"],
+            )
+        finally:
+            os.unlink(tmp_file)
+        actual = result.output
+        # We check the contents of the diff in `test_expression_diff`. All
+        # we need to check here is that color codes exist in the result.
+        self.assertIn("\033[1m", actual)
+        self.assertIn("\033[36m", actual)
+        self.assertIn("\033[32m", actual)
+        self.assertIn("\033[31m", actual)
+        self.assertIn("\033[0m", actual)
+
+    def test_detect_pos_only_arguments(self) -> None:
+        source, _ = read_data("py_38", "pep_570")
+        root = black.lib2to3_parse(source)
+        features = black.get_features_used(root)
+        self.assertIn(black.Feature.POS_ONLY_ARGUMENTS, features)
+        versions = black.detect_target_versions(root)
+        self.assertIn(black.TargetVersion.PY38, versions)
+
+    def test_detect_debug_f_strings(self) -> None:
+        root = black.lib2to3_parse("""f"{x=}" """)
+        features = black.get_features_used(root)
+        self.assertIn(black.Feature.DEBUG_F_STRINGS, features)
+        versions = black.detect_target_versions(root)
+        self.assertIn(black.TargetVersion.PY38, versions)
+
+        root = black.lib2to3_parse(
+            """f"{x}"\nf'{"="}'\nf'{(x:=5)}'\nf'{f(a="3=")}'\nf'{x:=10}'\n"""
+        )
+        features = black.get_features_used(root)
+        self.assertNotIn(black.Feature.DEBUG_F_STRINGS, features)
+
+        # We don't yet support feature version detection in nested f-strings
+        root = black.lib2to3_parse(
+            """f"heard a rumour that { f'{1+1=}' } ... seems like it could be true" """
+        )
+        features = black.get_features_used(root)
+        self.assertNotIn(black.Feature.DEBUG_F_STRINGS, features)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_string_quotes(self) -> None:
-        source, expected = read_data("string_quotes")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-        mode = black.FileMode.NO_STRING_NORMALIZATION
+        source, expected = read_data("miscellaneous", "string_quotes")
+        mode = black.Mode(preview=True)
+        assert_format(source, expected, mode)
+        mode = replace(mode, string_normalization=False)
         not_normalized = fs(source, mode=mode)
-        self.assertFormatEqual(source, not_normalized)
+        self.assertFormatEqual(source.replace("\\\n", ""), not_normalized)
         black.assert_equivalent(source, not_normalized)
-        black.assert_stable(source, not_normalized, line_length=ll, mode=mode)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_slices(self) -> None:
-        source, expected = read_data("slices")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_comments(self) -> None:
-        source, expected = read_data("comments")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_comments2(self) -> None:
-        source, expected = read_data("comments2")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_comments3(self) -> None:
-        source, expected = read_data("comments3")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_comments4(self) -> None:
-        source, expected = read_data("comments4")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_comments5(self) -> None:
-        source, expected = read_data("comments5")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_cantfit(self) -> None:
-        source, expected = read_data("cantfit")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        black.assert_stable(source, not_normalized, mode=mode)
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_import_spacing(self) -> None:
-        source, expected = read_data("import_spacing")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_composition(self) -> None:
-        source, expected = read_data("composition")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_empty_lines(self) -> None:
-        source, expected = read_data("empty_lines")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_string_prefixes(self) -> None:
-        source, expected = read_data("string_prefixes")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_python2(self) -> None:
-        source, expected = read_data("python2")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        # black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_python2_unicode_literals(self) -> None:
-        source, expected = read_data("python2_unicode_literals")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_stable(source, actual, line_length=ll)
+    def test_skip_source_first_line(self) -> None:
+        source, _ = read_data("miscellaneous", "invalid_header")
+        tmp_file = Path(black.dump_to_file(source))
+        # Full source should fail (invalid syntax at header)
+        self.invokeBlack([str(tmp_file), "--diff", "--check"], exit_code=123)
+        # So, skipping the first line should work
+        result = BlackRunner().invoke(
+            black.main, [str(tmp_file), "-x", f"--config={EMPTY_CONFIG}"]
+        )
+        self.assertEqual(result.exit_code, 0)
+        actual = tmp_file.read_text(encoding="utf-8")
+        self.assertFormatEqual(source, actual)
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_stub(self) -> None:
-        mode = black.FileMode.PYI
-        source, expected = read_data("stub.pyi")
-        actual = fs(source, mode=mode)
-        self.assertFormatEqual(expected, actual)
-        black.assert_stable(source, actual, line_length=ll, mode=mode)
+    def test_skip_source_first_line_when_mixing_newlines(self) -> None:
+        code_mixing_newlines = b"Header will be skipped\r\ni = [1,2,3]\nj = [1,2,3]\n"
+        expected = b"Header will be skipped\r\ni = [1, 2, 3]\nj = [1, 2, 3]\n"
+        with TemporaryDirectory() as workspace:
+            test_file = Path(workspace) / "skip_header.py"
+            test_file.write_bytes(code_mixing_newlines)
+            mode = replace(DEFAULT_MODE, skip_source_first_line=True)
+            ff(test_file, mode=mode, write_back=black.WriteBack.YES)
+            self.assertEqual(test_file.read_bytes(), expected)
+
+    def test_skip_magic_trailing_comma(self) -> None:
+        source, _ = read_data("simple_cases", "expression")
+        expected, _ = read_data(
+            "miscellaneous", "expression_skip_magic_trailing_comma.diff"
+        )
+        tmp_file = Path(black.dump_to_file(source))
+        diff_header = re.compile(
+            rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
+        )
+        try:
+            result = BlackRunner().invoke(
+                black.main, ["-C", "--diff", str(tmp_file), f"--config={EMPTY_CONFIG}"]
+            )
+            self.assertEqual(result.exit_code, 0)
+        finally:
+            os.unlink(tmp_file)
+        actual = result.output
+        actual = diff_header.sub(DETERMINISTIC_HEADER, actual)
+        actual = actual.rstrip() + "\n"  # the diff output has a trailing space
+        if expected != actual:
+            dump = black.dump_to_file(actual)
+            msg = (
+                "Expected diff isn't equal to the actual. If you made changes to"
+                " expression.py and this is an anticipated difference, overwrite"
+                " tests/data/miscellaneous/expression_skip_magic_trailing_comma.diff"
+                f" with {dump}"
+            )
+            self.assertEqual(expected, actual, msg)
 
     @patch("black.dump_to_file", dump_to_stderr)
-    def test_fmtonoff(self) -> None:
-        source, expected = read_data("fmtonoff")
+    def test_async_as_identifier(self) -> None:
+        source_path = get_case_path("miscellaneous", "async_as_identifier")
+        source, expected = read_data_from_file(source_path)
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        major, minor = sys.version_info[:2]
+        if major < 3 or (major <= 3 and minor < 7):
+            black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
+        # ensure black can parse this when the target is 3.6
+        self.invokeBlack([str(source_path), "--target-version", "py36"])
+        # but not on 3.7, because async/await is no longer an identifier
+        self.invokeBlack([str(source_path), "--target-version", "py37"], exit_code=123)
 
     @patch("black.dump_to_file", dump_to_stderr)
-    def test_remove_empty_parentheses_after_class(self) -> None:
-        source, expected = read_data("class_blank_parentheses")
+    def test_python37(self) -> None:
+        source_path = get_case_path("py_37", "python37")
+        source, expected = read_data_from_file(source_path)
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        major, minor = sys.version_info[:2]
+        if major > 3 or (major == 3 and minor >= 7):
+            black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
+        # ensure black can parse this when the target is 3.7
+        self.invokeBlack([str(source_path), "--target-version", "py37"])
+        # but not on 3.6, because we use async as a reserved keyword
+        self.invokeBlack([str(source_path), "--target-version", "py36"], exit_code=123)
+
+    def test_tab_comment_indentation(self) -> None:
+        contents_tab = "if 1:\n\tif 2:\n\t\tpass\n\t# comment\n\tpass\n"
+        contents_spc = "if 1:\n    if 2:\n        pass\n    # comment\n    pass\n"
+        self.assertFormatEqual(contents_spc, fs(contents_spc))
+        self.assertFormatEqual(contents_spc, fs(contents_tab))
+
+        contents_tab = "if 1:\n\tif 2:\n\t\tpass\n\t\t# comment\n\tpass\n"
+        contents_spc = "if 1:\n    if 2:\n        pass\n        # comment\n    pass\n"
+        self.assertFormatEqual(contents_spc, fs(contents_spc))
+        self.assertFormatEqual(contents_spc, fs(contents_tab))
+
+        # mixed tabs and spaces (valid Python 2 code)
+        contents_tab = "if 1:\n        if 2:\n\t\tpass\n\t# comment\n        pass\n"
+        contents_spc = "if 1:\n    if 2:\n        pass\n    # comment\n    pass\n"
+        self.assertFormatEqual(contents_spc, fs(contents_spc))
+        self.assertFormatEqual(contents_spc, fs(contents_tab))
+
+        contents_tab = "if 1:\n        if 2:\n\t\tpass\n\t\t# comment\n        pass\n"
+        contents_spc = "if 1:\n    if 2:\n        pass\n        # comment\n    pass\n"
+        self.assertFormatEqual(contents_spc, fs(contents_spc))
+        self.assertFormatEqual(contents_spc, fs(contents_tab))
+
+    def test_false_positive_symlink_output_issue_3384(self) -> None:
+        # Emulate the behavior when using the CLI (`black ./child  --verbose`), which
+        # involves patching some `pathlib.Path` methods. In particular, `is_dir` is
+        # patched only on its first call: when checking if "./child" is a directory it
+        # should return True. The "./child" folder exists relative to the cwd when
+        # running from CLI, but fails when running the tests because cwd is different
+        project_root = Path(THIS_DIR / "data" / "nested_gitignore_tests")
+        working_directory = project_root / "root"
+        target_abspath = working_directory / "child"
+        target_contents = (
+            src.relative_to(working_directory) for src in target_abspath.iterdir()
+        )
 
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_new_line_between_class_and_code(self) -> None:
-        source, expected = read_data("class_methods_new_line")
-        actual = fs(source)
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        def mock_n_calls(responses: List[bool]) -> Callable[[], bool]:
+            def _mocked_calls() -> bool:
+                if responses:
+                    return responses.pop(0)
+                return False
+
+            return _mocked_calls
+
+        with patch("pathlib.Path.iterdir", return_value=target_contents), patch(
+            "pathlib.Path.cwd", return_value=working_directory
+        ), patch("pathlib.Path.is_dir", side_effect=mock_n_calls([True])):
+            ctx = FakeContext()
+            ctx.obj["root"] = project_root
+            report = MagicMock(verbose=True)
+            black.get_sources(
+                ctx=ctx,
+                src=("./child",),
+                quiet=False,
+                verbose=True,
+                include=DEFAULT_INCLUDE,
+                exclude=None,
+                report=report,
+                extend_exclude=None,
+                force_exclude=None,
+                stdin_filename=None,
+            )
+        assert not any(
+            mock_args[1].startswith("is a symbolic link that points outside")
+            for _, mock_args, _ in report.path_ignored.mock_calls
+        ), "A symbolic link was reported."
+        report.path_ignored.assert_called_once_with(
+            Path("child", "b.py"), "matches a .gitignore file content"
+        )
 
-    def test_report(self) -> None:
-        report = black.Report()
+    def test_report_verbose(self) -> None:
+        report = Report(verbose=True)
         out_lines = []
         err_lines = []
 
@@ -389,7 +541,7 @@ class BlackTestCase(unittest.TestCase):
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.out", out), patch("black.err", err):
+        with patch("black.output._out", out), patch("black.output._err", err):
             report.done(Path("f1"), black.Changed.NO)
             self.assertEqual(len(out_lines), 1)
             self.assertEqual(len(err_lines), 0)
@@ -422,8 +574,8 @@ class BlackTestCase(unittest.TestCase):
             self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
             self.assertEqual(
                 unstyle(str(report)),
-                "1 file reformatted, 2 files left unchanged, "
-                "1 file failed to reformat.",
+                "1 file reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.done(Path("f3"), black.Changed.YES)
@@ -432,8 +584,8 @@ class BlackTestCase(unittest.TestCase):
             self.assertEqual(out_lines[-1], "reformatted f3")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 2 files left unchanged, "
-                "1 file failed to reformat.",
+                "2 files reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.failed(Path("e2"), "boom")
@@ -442,70 +594,46 @@ class BlackTestCase(unittest.TestCase):
             self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 2 files left unchanged, "
-                "2 files failed to reformat.",
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
             )
             self.assertEqual(report.return_code, 123)
-            report.done(Path("f4"), black.Changed.NO)
+            report.path_ignored(Path("wat"), "no match")
             self.assertEqual(len(out_lines), 5)
             self.assertEqual(len(err_lines), 2)
+            self.assertEqual(out_lines[-1], "wat ignored: no match")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 6)
+            self.assertEqual(len(err_lines), 2)
             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 3 files left unchanged, "
-                "2 files failed to reformat.",
+                "2 files reformatted, 3 files left unchanged, 2 files failed to"
+                " reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.check = True
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files would be reformatted, 3 files would be left unchanged, "
-                "2 files would fail to reformat.",
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
+            )
+            report.check = False
+            report.diff = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
             )
 
-    def test_is_python36(self) -> None:
-        node = black.lib2to3_parse("def f(*, arg): ...\n")
-        self.assertFalse(black.is_python36(node))
-        node = black.lib2to3_parse("def f(*, arg,): ...\n")
-        self.assertTrue(black.is_python36(node))
-        node = black.lib2to3_parse("def f(*, arg): f'string'\n")
-        self.assertTrue(black.is_python36(node))
-        source, expected = read_data("function")
-        node = black.lib2to3_parse(source)
-        self.assertTrue(black.is_python36(node))
-        node = black.lib2to3_parse(expected)
-        self.assertTrue(black.is_python36(node))
-        source, expected = read_data("expression")
-        node = black.lib2to3_parse(source)
-        self.assertFalse(black.is_python36(node))
-        node = black.lib2to3_parse(expected)
-        self.assertFalse(black.is_python36(node))
-
-    def test_get_future_imports(self) -> None:
-        node = black.lib2to3_parse("\n")
-        self.assertEqual(set(), black.get_future_imports(node))
-        node = black.lib2to3_parse("from __future__ import black\n")
-        self.assertEqual({"black"}, black.get_future_imports(node))
-        node = black.lib2to3_parse("from __future__ import multiple, imports\n")
-        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
-        node = black.lib2to3_parse("from __future__ import (parenthesized, imports)\n")
-        self.assertEqual({"parenthesized", "imports"}, black.get_future_imports(node))
-        node = black.lib2to3_parse(
-            "from __future__ import multiple\nfrom __future__ import imports\n"
-        )
-        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
-        node = black.lib2to3_parse("# comment\nfrom __future__ import black\n")
-        self.assertEqual({"black"}, black.get_future_imports(node))
-        node = black.lib2to3_parse('"""docstring"""\nfrom __future__ import black\n')
-        self.assertEqual({"black"}, black.get_future_imports(node))
-        node = black.lib2to3_parse("some(other, code)\nfrom __future__ import black\n")
-        self.assertEqual(set(), black.get_future_imports(node))
-        node = black.lib2to3_parse("from some.module import black\n")
-        self.assertEqual(set(), black.get_future_imports(node))
-
-    def test_debug_visitor(self) -> None:
-        source, _ = read_data("debug_visitor.py")
-        expected, _ = read_data("debug_visitor.out")
+    def test_report_quiet(self) -> None:
+        report = Report(quiet=True)
         out_lines = []
         err_lines = []
 
@@ -515,45 +643,91 @@ class BlackTestCase(unittest.TestCase):
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.out", out), patch("black.err", err):
-            black.DebugVisitor.show(source)
-        actual = "\n".join(out_lines) + "\n"
-        log_name = ""
-        if expected != actual:
-            log_name = black.dump_to_file(*out_lines)
-        self.assertEqual(
-            expected,
-            actual,
-            f"AST print out is different. Actual version dumped to {log_name}",
-        )
-
-    def test_format_file_contents(self) -> None:
-        empty = ""
-        with self.assertRaises(black.NothingChanged):
-            black.format_file_contents(empty, line_length=ll, fast=False)
-        just_nl = "\n"
-        with self.assertRaises(black.NothingChanged):
-            black.format_file_contents(just_nl, line_length=ll, fast=False)
-        same = "l = [1, 2, 3]\n"
-        with self.assertRaises(black.NothingChanged):
-            black.format_file_contents(same, line_length=ll, fast=False)
-        different = "l = [1,2,3]"
-        expected = same
-        actual = black.format_file_contents(different, line_length=ll, fast=False)
-        self.assertEqual(expected, actual)
-        invalid = "return if you can"
-        with self.assertRaises(ValueError) as e:
-            black.format_file_contents(invalid, line_length=ll, fast=False)
-        self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
-
-    def test_endmarker(self) -> None:
-        n = black.lib2to3_parse("\n")
-        self.assertEqual(n.type, black.syms.file_input)
-        self.assertEqual(len(n.children), 1)
-        self.assertEqual(n.children[0].type, black.token.ENDMARKER)
+        with patch("black.output._out", out), patch("black.output._err", err):
+            report.done(Path("f1"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
+            self.assertEqual(report.return_code, 0)
+            report.done(Path("f2"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 1 file left unchanged."
+            )
+            report.done(Path("f3"), black.Changed.CACHED)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 2 files left unchanged."
+            )
+            self.assertEqual(report.return_code, 0)
+            report.check = True
+            self.assertEqual(report.return_code, 1)
+            report.check = False
+            report.failed(Path("e1"), "boom")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "1 file reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f3"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.failed(Path("e2"), "boom")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.path_ignored(Path("wat"), "no match")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 3 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.check = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
+            )
+            report.check = False
+            report.diff = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
+            )
 
-    @unittest.skipIf(os.environ.get("SKIP_AST_PRINT"), "user set SKIP_AST_PRINT")
-    def test_assertFormatEqual(self) -> None:
+    def test_report_normal(self) -> None:
+        report = black.Report()
         out_lines = []
         err_lines = []
 
@@ -563,315 +737,1575 @@ class BlackTestCase(unittest.TestCase):
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.out", out), patch("black.err", err):
-            with self.assertRaises(AssertionError):
-                self.assertFormatEqual("l = [1, 2, 3]", "l = [1, 2, 3,]")
+        with patch("black.output._out", out), patch("black.output._err", err):
+            report.done(Path("f1"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
+            self.assertEqual(report.return_code, 0)
+            report.done(Path("f2"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(out_lines[-1], "reformatted f2")
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 1 file left unchanged."
+            )
+            report.done(Path("f3"), black.Changed.CACHED)
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(out_lines[-1], "reformatted f2")
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 2 files left unchanged."
+            )
+            self.assertEqual(report.return_code, 0)
+            report.check = True
+            self.assertEqual(report.return_code, 1)
+            report.check = False
+            report.failed(Path("e1"), "boom")
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "1 file reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f3"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(out_lines[-1], "reformatted f3")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 1 file failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.failed(Path("e2"), "boom")
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.path_ignored(Path("wat"), "no match")
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 3 files left unchanged, 2 files failed to"
+                " reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.check = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
+            )
+            report.check = False
+            report.diff = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, 2"
+                " files would fail to reformat.",
+            )
 
-        out_str = "".join(out_lines)
-        self.assertTrue("Expected tree:" in out_str)
-        self.assertTrue("Actual tree:" in out_str)
-        self.assertEqual("".join(err_lines), "")
+    def test_lib2to3_parse(self) -> None:
+        with self.assertRaises(black.InvalidInput):
+            black.lib2to3_parse("invalid syntax")
+
+        straddling = "x + y"
+        black.lib2to3_parse(straddling)
+        black.lib2to3_parse(straddling, {TargetVersion.PY36})
+
+        py2_only = "print x"
+        with self.assertRaises(black.InvalidInput):
+            black.lib2to3_parse(py2_only, {TargetVersion.PY36})
+
+        py3_only = "exec(x, end=y)"
+        black.lib2to3_parse(py3_only)
+        black.lib2to3_parse(py3_only, {TargetVersion.PY36})
+
+    def test_get_features_used_decorator(self) -> None:
+        # Test the feature detection of new decorator syntax
+        # since this makes some test cases of test_get_features_used()
+        # fails if it fails, this is tested first so that a useful case
+        # is identified
+        simples, relaxed = read_data("miscellaneous", "decorators")
+        # skip explanation comments at the top of the file
+        for simple_test in simples.split("##")[1:]:
+            node = black.lib2to3_parse(simple_test)
+            decorator = str(node.children[0].children[0]).strip()
+            self.assertNotIn(
+                Feature.RELAXED_DECORATORS,
+                black.get_features_used(node),
+                msg=(
+                    f"decorator '{decorator}' follows python<=3.8 syntax"
+                    "but is detected as 3.9+"
+                    # f"The full node is\n{node!r}"
+                ),
+            )
+        # skip the '# output' comment at the top of the output part
+        for relaxed_test in relaxed.split("##")[1:]:
+            node = black.lib2to3_parse(relaxed_test)
+            decorator = str(node.children[0].children[0]).strip()
+            self.assertIn(
+                Feature.RELAXED_DECORATORS,
+                black.get_features_used(node),
+                msg=(
+                    f"decorator '{decorator}' uses python3.9+ syntax"
+                    "but is detected as python<=3.8"
+                    # f"The full node is\n{node!r}"
+                ),
+            )
 
-    def test_cache_broken_file(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace:
-            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
-            with cache_file.open("w") as fobj:
-                fobj.write("this is not a pickle")
-            self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH, mode), {})
-            src = (workspace / "test.py").resolve()
-            with src.open("w") as fobj:
-                fobj.write("print('hello')")
-            result = CliRunner().invoke(black.main, [str(src)])
-            self.assertEqual(result.exit_code, 0)
-            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertIn(src, cache)
+    def test_get_features_used(self) -> None:
+        node = black.lib2to3_parse("def f(*, arg): ...\n")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("def f(*, arg,): ...\n")
+        self.assertEqual(black.get_features_used(node), {Feature.TRAILING_COMMA_IN_DEF})
+        node = black.lib2to3_parse("f(*arg,)\n")
+        self.assertEqual(
+            black.get_features_used(node), {Feature.TRAILING_COMMA_IN_CALL}
+        )
+        node = black.lib2to3_parse("def f(*, arg): f'string'\n")
+        self.assertEqual(black.get_features_used(node), {Feature.F_STRINGS})
+        node = black.lib2to3_parse("123_456\n")
+        self.assertEqual(black.get_features_used(node), {Feature.NUMERIC_UNDERSCORES})
+        node = black.lib2to3_parse("123456\n")
+        self.assertEqual(black.get_features_used(node), set())
+        source, expected = read_data("simple_cases", "function")
+        node = black.lib2to3_parse(source)
+        expected_features = {
+            Feature.TRAILING_COMMA_IN_CALL,
+            Feature.TRAILING_COMMA_IN_DEF,
+            Feature.F_STRINGS,
+        }
+        self.assertEqual(black.get_features_used(node), expected_features)
+        node = black.lib2to3_parse(expected)
+        self.assertEqual(black.get_features_used(node), expected_features)
+        source, expected = read_data("simple_cases", "expression")
+        node = black.lib2to3_parse(source)
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse(expected)
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("lambda a, /, b: ...")
+        self.assertEqual(black.get_features_used(node), {Feature.POS_ONLY_ARGUMENTS})
+        node = black.lib2to3_parse("def fn(a, /, b): ...")
+        self.assertEqual(black.get_features_used(node), {Feature.POS_ONLY_ARGUMENTS})
+        node = black.lib2to3_parse("def fn(): yield a, b")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("def fn(): return a, b")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("def fn(): yield *b, c")
+        self.assertEqual(black.get_features_used(node), {Feature.UNPACKING_ON_FLOW})
+        node = black.lib2to3_parse("def fn(): return a, *b, c")
+        self.assertEqual(black.get_features_used(node), {Feature.UNPACKING_ON_FLOW})
+        node = black.lib2to3_parse("x = a, *b, c")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("x: Any = regular")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("x: Any = (regular, regular)")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("x: Any = Complex(Type(1))[something]")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("x: Tuple[int, ...] = a, b, c")
+        self.assertEqual(
+            black.get_features_used(node), {Feature.ANN_ASSIGN_EXTENDED_RHS}
+        )
+        node = black.lib2to3_parse("try: pass\nexcept Something: pass")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("try: pass\nexcept (*Something,): pass")
+        self.assertEqual(black.get_features_used(node), set())
+        node = black.lib2to3_parse("try: pass\nexcept *Group: pass")
+        self.assertEqual(black.get_features_used(node), {Feature.EXCEPT_STAR})
+        node = black.lib2to3_parse("a[*b]")
+        self.assertEqual(black.get_features_used(node), {Feature.VARIADIC_GENERICS})
+        node = black.lib2to3_parse("a[x, *y(), z] = t")
+        self.assertEqual(black.get_features_used(node), {Feature.VARIADIC_GENERICS})
+        node = black.lib2to3_parse("def fn(*args: *T): pass")
+        self.assertEqual(black.get_features_used(node), {Feature.VARIADIC_GENERICS})
+
+    def test_get_features_used_for_future_flags(self) -> None:
+        for src, features in [
+            ("from __future__ import annotations", {Feature.FUTURE_ANNOTATIONS}),
+            (
+                "from __future__ import (other, annotations)",
+                {Feature.FUTURE_ANNOTATIONS},
+            ),
+            ("a = 1 + 2\nfrom something import annotations", set()),
+            ("from __future__ import x, y", set()),
+        ]:
+            with self.subTest(src=src, features=features):
+                node = black.lib2to3_parse(src)
+                future_imports = black.get_future_imports(node)
+                self.assertEqual(
+                    black.get_features_used(node, future_imports=future_imports),
+                    features,
+                )
 
-    def test_cache_single_file_already_cached(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace:
-            src = (workspace / "test.py").resolve()
-            with src.open("w") as fobj:
-                fobj.write("print('hello')")
-            black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH, mode)
-            result = CliRunner().invoke(black.main, [str(src)])
-            self.assertEqual(result.exit_code, 0)
-            with src.open("r") as fobj:
-                self.assertEqual(fobj.read(), "print('hello')")
+    def test_get_future_imports(self) -> None:
+        node = black.lib2to3_parse("\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import black\n")
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import multiple, imports\n")
+        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import (parenthesized, imports)\n")
+        self.assertEqual({"parenthesized", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse(
+            "from __future__ import multiple\nfrom __future__ import imports\n"
+        )
+        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("# comment\nfrom __future__ import black\n")
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse('"""docstring"""\nfrom __future__ import black\n')
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("some(other, code)\nfrom __future__ import black\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+        node = black.lib2to3_parse("from some.module import black\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+        node = black.lib2to3_parse(
+            "from __future__ import unicode_literals as _unicode_literals"
+        )
+        self.assertEqual({"unicode_literals"}, black.get_future_imports(node))
+        node = black.lib2to3_parse(
+            "from __future__ import unicode_literals as _lol, print"
+        )
+        self.assertEqual({"unicode_literals", "print"}, black.get_future_imports(node))
 
-    @event_loop(close=False)
-    def test_cache_multiple_files(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace, patch(
-            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
-        ):
-            one = (workspace / "one.py").resolve()
-            with one.open("w") as fobj:
-                fobj.write("print('hello')")
-            two = (workspace / "two.py").resolve()
-            with two.open("w") as fobj:
-                fobj.write("print('hello')")
-            black.write_cache({}, [one], black.DEFAULT_LINE_LENGTH, mode)
-            result = CliRunner().invoke(black.main, [str(workspace)])
-            self.assertEqual(result.exit_code, 0)
-            with one.open("r") as fobj:
-                self.assertEqual(fobj.read(), "print('hello')")
-            with two.open("r") as fobj:
-                self.assertEqual(fobj.read(), 'print("hello")\n')
-            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertIn(one, cache)
-            self.assertIn(two, cache)
-
-    def test_no_cache_when_writeback_diff(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace:
-            src = (workspace / "test.py").resolve()
-            with src.open("w") as fobj:
-                fobj.write("print('hello')")
-            result = CliRunner().invoke(black.main, [str(src), "--diff"])
-            self.assertEqual(result.exit_code, 0)
-            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertFalse(cache_file.exists())
+    @pytest.mark.incompatible_with_mypyc
+    def test_debug_visitor(self) -> None:
+        source, _ = read_data("miscellaneous", "debug_visitor")
+        expected, _ = read_data("miscellaneous", "debug_visitor.out")
+        out_lines = []
+        err_lines = []
 
-    def test_no_cache_when_stdin(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir():
-            result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
-            self.assertEqual(result.exit_code, 0)
-            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertFalse(cache_file.exists())
+        def out(msg: str, **kwargs: Any) -> None:
+            out_lines.append(msg)
 
-    def test_read_cache_no_cachefile(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir():
-            self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH, mode), {})
+        def err(msg: str, **kwargs: Any) -> None:
+            err_lines.append(msg)
 
-    def test_write_cache_read_cache(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace:
-            src = (workspace / "test.py").resolve()
-            src.touch()
-            black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH, mode)
-            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertIn(src, cache)
-            self.assertEqual(cache[src], black.get_cache_info(src))
+        with patch("black.debug.out", out):
+            DebugVisitor.show(source)
+        actual = "\n".join(out_lines) + "\n"
+        log_name = ""
+        if expected != actual:
+            log_name = black.dump_to_file(*out_lines)
+        self.assertEqual(
+            expected,
+            actual,
+            f"AST print out is different. Actual version dumped to {log_name}",
+        )
 
-    def test_filter_cached(self) -> None:
-        with TemporaryDirectory() as workspace:
-            path = Path(workspace)
-            uncached = (path / "uncached").resolve()
-            cached = (path / "cached").resolve()
-            cached_but_changed = (path / "changed").resolve()
-            uncached.touch()
-            cached.touch()
-            cached_but_changed.touch()
-            cache = {cached: black.get_cache_info(cached), cached_but_changed: (0.0, 0)}
-            todo, done = black.filter_cached(
-                cache, [uncached, cached, cached_but_changed]
-            )
-            self.assertEqual(todo, [uncached, cached_but_changed])
-            self.assertEqual(done, [cached])
+    def test_format_file_contents(self) -> None:
+        mode = DEFAULT_MODE
+        empty = ""
+        with self.assertRaises(black.NothingChanged):
+            black.format_file_contents(empty, mode=mode, fast=False)
+        just_nl = "\n"
+        with self.assertRaises(black.NothingChanged):
+            black.format_file_contents(just_nl, mode=mode, fast=False)
+        same = "j = [1, 2, 3]\n"
+        with self.assertRaises(black.NothingChanged):
+            black.format_file_contents(same, mode=mode, fast=False)
+        different = "j = [1,2,3]"
+        expected = same
+        actual = black.format_file_contents(different, mode=mode, fast=False)
+        self.assertEqual(expected, actual)
+        invalid = "return if you can"
+        with self.assertRaises(black.InvalidInput) as e:
+            black.format_file_contents(invalid, mode=mode, fast=False)
+        self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
 
-    def test_write_cache_creates_directory_if_needed(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir(exists=False) as workspace:
-            self.assertFalse(workspace.exists())
-            black.write_cache({}, [], black.DEFAULT_LINE_LENGTH, mode)
-            self.assertTrue(workspace.exists())
+        mode = black.Mode(preview=True)
+        just_crlf = "\r\n"
+        with self.assertRaises(black.NothingChanged):
+            black.format_file_contents(just_crlf, mode=mode, fast=False)
+        just_whitespace_nl = "\n\t\n \n\t \n \t\n\n"
+        actual = black.format_file_contents(just_whitespace_nl, mode=mode, fast=False)
+        self.assertEqual("\n", actual)
+        just_whitespace_crlf = "\r\n\t\r\n \r\n\t \r\n \t\r\n\r\n"
+        actual = black.format_file_contents(just_whitespace_crlf, mode=mode, fast=False)
+        self.assertEqual("\r\n", actual)
 
-    @event_loop(close=False)
-    def test_failed_formatting_does_not_get_cached(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace, patch(
-            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
-        ):
-            failing = (workspace / "failing.py").resolve()
-            with failing.open("w") as fobj:
-                fobj.write("not actually python")
-            clean = (workspace / "clean.py").resolve()
-            with clean.open("w") as fobj:
-                fobj.write('print("hello")\n')
-            result = CliRunner().invoke(black.main, [str(workspace)])
-            self.assertEqual(result.exit_code, 123)
-            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)
-            self.assertNotIn(failing, cache)
-            self.assertIn(clean, cache)
+    def test_endmarker(self) -> None:
+        n = black.lib2to3_parse("\n")
+        self.assertEqual(n.type, black.syms.file_input)
+        self.assertEqual(len(n.children), 1)
+        self.assertEqual(n.children[0].type, black.token.ENDMARKER)
 
-    def test_write_cache_write_fail(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir(), patch.object(Path, "open") as mock:
-            mock.side_effect = OSError
-            black.write_cache({}, [], black.DEFAULT_LINE_LENGTH, mode)
+    @pytest.mark.incompatible_with_mypyc
+    @unittest.skipIf(os.environ.get("SKIP_AST_PRINT"), "user set SKIP_AST_PRINT")
+    def test_assertFormatEqual(self) -> None:
+        out_lines = []
+        err_lines = []
+
+        def out(msg: str, **kwargs: Any) -> None:
+            out_lines.append(msg)
+
+        def err(msg: str, **kwargs: Any) -> None:
+            err_lines.append(msg)
+
+        with patch("black.output._out", out), patch("black.output._err", err):
+            with self.assertRaises(AssertionError):
+                self.assertFormatEqual("j = [1, 2, 3]", "j = [1, 2, 3,]")
 
-    @event_loop(close=False)
+        out_str = "".join(out_lines)
+        self.assertIn("Expected tree:", out_str)
+        self.assertIn("Actual tree:", out_str)
+        self.assertEqual("".join(err_lines), "")
+
+    @event_loop()
+    @patch("concurrent.futures.ProcessPoolExecutor", MagicMock(side_effect=OSError))
+    def test_works_in_mono_process_only_environment(self) -> None:
+        with cache_dir() as workspace:
+            for f in [
+                (workspace / "one.py").resolve(),
+                (workspace / "two.py").resolve(),
+            ]:
+                f.write_text('print("hello")\n', encoding="utf-8")
+            self.invokeBlack([str(workspace)])
+
+    @event_loop()
     def test_check_diff_use_together(self) -> None:
         with cache_dir():
             # Files which will be reformatted.
-            src1 = (THIS_DIR / "string_quotes.py").resolve()
-            result = CliRunner().invoke(black.main, [str(src1), "--diff", "--check"])
-            self.assertEqual(result.exit_code, 1)
-
+            src1 = get_case_path("miscellaneous", "string_quotes")
+            self.invokeBlack([str(src1), "--diff", "--check"], exit_code=1)
             # Files which will not be reformatted.
-            src2 = (THIS_DIR / "composition.py").resolve()
-            result = CliRunner().invoke(black.main, [str(src2), "--diff", "--check"])
-            self.assertEqual(result.exit_code, 0)
-
+            src2 = get_case_path("simple_cases", "composition")
+            self.invokeBlack([str(src2), "--diff", "--check"])
             # Multi file command.
-            result = CliRunner().invoke(
-                black.main, [str(src1), str(src2), "--diff", "--check"]
-            )
-            self.assertEqual(result.exit_code, 1, result.output)
+            self.invokeBlack([str(src1), str(src2), "--diff", "--check"], exit_code=1)
 
-    def test_no_files(self) -> None:
+    def test_no_src_fails(self) -> None:
         with cache_dir():
-            # Without an argument, black exits with error code 0.
-            result = CliRunner().invoke(black.main, [])
-            self.assertEqual(result.exit_code, 0)
+            self.invokeBlack([], exit_code=1)
+
+    def test_src_and_code_fails(self) -> None:
+        with cache_dir():
+            self.invokeBlack([".", "-c", "0"], exit_code=1)
 
     def test_broken_symlink(self) -> None:
         with cache_dir() as workspace:
             symlink = workspace / "broken_link.py"
             try:
                 symlink.symlink_to("nonexistent.py")
-            except OSError as e:
+            except (OSError, NotImplementedError) as e:
                 self.skipTest(f"Can't create symlinks: {e}")
-            result = CliRunner().invoke(black.main, [str(workspace.resolve())])
-            self.assertEqual(result.exit_code, 0)
-
-    def test_read_cache_line_lengths(self) -> None:
-        mode = black.FileMode.AUTO_DETECT
-        with cache_dir() as workspace:
-            path = (workspace / "file.py").resolve()
-            path.touch()
-            black.write_cache({}, [path], 1, mode)
-            one = black.read_cache(1, mode)
-            self.assertIn(path, one)
-            two = black.read_cache(2, mode)
-            self.assertNotIn(path, two)
+            self.invokeBlack([str(workspace.resolve())])
 
     def test_single_file_force_pyi(self) -> None:
-        reg_mode = black.FileMode.AUTO_DETECT
-        pyi_mode = black.FileMode.PYI
-        contents, expected = read_data("force_pyi")
+        pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
+        contents, expected = read_data("miscellaneous", "force_pyi")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
-            with open(path, "w") as fh:
-                fh.write(contents)
-            result = CliRunner().invoke(black.main, [str(path), "--pyi"])
-            self.assertEqual(result.exit_code, 0)
-            with open(path, "r") as fh:
-                actual = fh.read()
+            path.write_text(contents, encoding="utf-8")
+            self.invokeBlack([str(path), "--pyi"])
+            actual = path.read_text(encoding="utf-8")
             # verify cache with --pyi is separate
-            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, pyi_mode)
-            self.assertIn(path, pyi_cache)
-            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
-            self.assertNotIn(path, normal_cache)
-        self.assertEqual(actual, expected)
+            pyi_cache = black.read_cache(pyi_mode)
+            self.assertIn(str(path), pyi_cache)
+            normal_cache = black.read_cache(DEFAULT_MODE)
+            self.assertNotIn(str(path), normal_cache)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(contents, actual)
+        black.assert_stable(contents, actual, pyi_mode)
 
-    @event_loop(close=False)
+    @event_loop()
     def test_multi_file_force_pyi(self) -> None:
-        reg_mode = black.FileMode.AUTO_DETECT
-        pyi_mode = black.FileMode.PYI
-        contents, expected = read_data("force_pyi")
+        reg_mode = DEFAULT_MODE
+        pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
+        contents, expected = read_data("miscellaneous", "force_pyi")
         with cache_dir() as workspace:
             paths = [
                 (workspace / "file1.py").resolve(),
                 (workspace / "file2.py").resolve(),
             ]
             for path in paths:
-                with open(path, "w") as fh:
-                    fh.write(contents)
-            result = CliRunner().invoke(black.main, [str(p) for p in paths] + ["--pyi"])
-            self.assertEqual(result.exit_code, 0)
+                path.write_text(contents, encoding="utf-8")
+            self.invokeBlack([str(p) for p in paths] + ["--pyi"])
             for path in paths:
-                with open(path, "r") as fh:
-                    actual = fh.read()
+                actual = path.read_text(encoding="utf-8")
                 self.assertEqual(actual, expected)
             # verify cache with --pyi is separate
-            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, pyi_mode)
-            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            pyi_cache = black.read_cache(pyi_mode)
+            normal_cache = black.read_cache(reg_mode)
             for path in paths:
-                self.assertIn(path, pyi_cache)
-                self.assertNotIn(path, normal_cache)
+                self.assertIn(str(path), pyi_cache)
+                self.assertNotIn(str(path), normal_cache)
 
     def test_pipe_force_pyi(self) -> None:
-        source, expected = read_data("force_pyi")
-        result = CliRunner().invoke(black.main, ["-", "-q", "--pyi"], input=source)
+        source, expected = read_data("miscellaneous", "force_pyi")
+        result = CliRunner().invoke(
+            black.main, ["-", "-q", "--pyi"], input=BytesIO(source.encode("utf-8"))
+        )
         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)
 
     def test_single_file_force_py36(self) -> None:
-        reg_mode = black.FileMode.AUTO_DETECT
-        py36_mode = black.FileMode.PYTHON36
-        source, expected = read_data("force_py36")
+        reg_mode = DEFAULT_MODE
+        py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
+        source, expected = read_data("miscellaneous", "force_py36")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
-            with open(path, "w") as fh:
-                fh.write(source)
-            result = CliRunner().invoke(black.main, [str(path), "--py36"])
-            self.assertEqual(result.exit_code, 0)
-            with open(path, "r") as fh:
-                actual = fh.read()
-            # verify cache with --py36 is separate
-            py36_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, py36_mode)
-            self.assertIn(path, py36_cache)
-            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
-            self.assertNotIn(path, normal_cache)
+            path.write_text(source, encoding="utf-8")
+            self.invokeBlack([str(path), *PY36_ARGS])
+            actual = path.read_text(encoding="utf-8")
+            # verify cache with --target-version is separate
+            py36_cache = black.read_cache(py36_mode)
+            self.assertIn(str(path), py36_cache)
+            normal_cache = black.read_cache(reg_mode)
+            self.assertNotIn(str(path), normal_cache)
         self.assertEqual(actual, expected)
 
-    @event_loop(close=False)
+    @event_loop()
     def test_multi_file_force_py36(self) -> None:
-        reg_mode = black.FileMode.AUTO_DETECT
-        py36_mode = black.FileMode.PYTHON36
-        source, expected = read_data("force_py36")
+        reg_mode = DEFAULT_MODE
+        py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
+        source, expected = read_data("miscellaneous", "force_py36")
         with cache_dir() as workspace:
             paths = [
                 (workspace / "file1.py").resolve(),
                 (workspace / "file2.py").resolve(),
             ]
             for path in paths:
-                with open(path, "w") as fh:
-                    fh.write(source)
-            result = CliRunner().invoke(
-                black.main, [str(p) for p in paths] + ["--py36"]
-            )
-            self.assertEqual(result.exit_code, 0)
+                path.write_text(source, encoding="utf-8")
+            self.invokeBlack([str(p) for p in paths] + PY36_ARGS)
             for path in paths:
-                with open(path, "r") as fh:
-                    actual = fh.read()
+                actual = path.read_text(encoding="utf-8")
                 self.assertEqual(actual, expected)
-            # verify cache with --py36 is separate
-            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, py36_mode)
-            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            # verify cache with --target-version is separate
+            pyi_cache = black.read_cache(py36_mode)
+            normal_cache = black.read_cache(reg_mode)
             for path in paths:
-                self.assertIn(path, pyi_cache)
-                self.assertNotIn(path, normal_cache)
+                self.assertIn(str(path), pyi_cache)
+                self.assertNotIn(str(path), normal_cache)
 
     def test_pipe_force_py36(self) -> None:
-        source, expected = read_data("force_py36")
-        result = CliRunner().invoke(black.main, ["-", "-q", "--py36"], input=source)
+        source, expected = read_data("miscellaneous", "force_py36")
+        result = CliRunner().invoke(
+            black.main,
+            ["-", "-q", "--target-version=py36"],
+            input=BytesIO(source.encode("utf-8")),
+        )
         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)
 
+    @pytest.mark.incompatible_with_mypyc
+    def test_reformat_one_with_stdin(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            path = Path("-")
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once()
+            report.done.assert_called_with(path, black.Changed.YES)
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_reformat_one_with_stdin_filename(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            p = "foo.py"
+            path = Path(f"__BLACK_STDIN_FILENAME__{p}")
+            expected = Path(p)
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once_with(
+                fast=True, write_back=black.WriteBack.YES, mode=DEFAULT_MODE
+            )
+            # __BLACK_STDIN_FILENAME__ should have been stripped
+            report.done.assert_called_with(expected, black.Changed.YES)
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_reformat_one_with_stdin_filename_pyi(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            p = "foo.pyi"
+            path = Path(f"__BLACK_STDIN_FILENAME__{p}")
+            expected = Path(p)
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once_with(
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=replace(DEFAULT_MODE, is_pyi=True),
+            )
+            # __BLACK_STDIN_FILENAME__ should have been stripped
+            report.done.assert_called_with(expected, black.Changed.YES)
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_reformat_one_with_stdin_filename_ipynb(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            p = "foo.ipynb"
+            path = Path(f"__BLACK_STDIN_FILENAME__{p}")
+            expected = Path(p)
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once_with(
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=replace(DEFAULT_MODE, is_ipynb=True),
+            )
+            # __BLACK_STDIN_FILENAME__ should have been stripped
+            report.done.assert_called_with(expected, black.Changed.YES)
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_reformat_one_with_stdin_and_existing_path(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            # Even with an existing file, since we are forcing stdin, black
+            # should output to stdout and not modify the file inplace
+            p = THIS_DIR / "data" / "simple_cases" / "collections.py"
+            # Make sure is_file actually returns True
+            self.assertTrue(p.is_file())
+            path = Path(f"__BLACK_STDIN_FILENAME__{p}")
+            expected = Path(p)
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once()
+            # __BLACK_STDIN_FILENAME__ should have been stripped
+            report.done.assert_called_with(expected, black.Changed.YES)
+
+    def test_reformat_one_with_stdin_empty(self) -> None:
+        cases = [
+            ("", ""),
+            ("\n", "\n"),
+            ("\r\n", "\r\n"),
+            (" \t", ""),
+            (" \t\n\t ", "\n"),
+            (" \t\r\n\t ", "\r\n"),
+        ]
+
+        def _new_wrapper(
+            output: io.StringIO, io_TextIOWrapper: Type[io.TextIOWrapper]
+        ) -> Callable[[Any, Any], io.TextIOWrapper]:
+            def get_output(*args: Any, **kwargs: Any) -> io.TextIOWrapper:
+                if args == (sys.stdout.buffer,):
+                    # It's `format_stdin_to_stdout()` calling `io.TextIOWrapper()`,
+                    # return our mock object.
+                    return output
+                # It's something else (i.e. `decode_bytes()`) calling
+                # `io.TextIOWrapper()`, pass through to the original implementation.
+                # See discussion in https://github.com/psf/black/pull/2489
+                return io_TextIOWrapper(*args, **kwargs)
+
+            return get_output
+
+        mode = black.Mode(preview=True)
+        for content, expected in cases:
+            output = io.StringIO()
+            io_TextIOWrapper = io.TextIOWrapper
+
+            with patch("io.TextIOWrapper", _new_wrapper(output, io_TextIOWrapper)):
+                try:
+                    black.format_stdin_to_stdout(
+                        fast=True,
+                        content=content,
+                        write_back=black.WriteBack.YES,
+                        mode=mode,
+                    )
+                except io.UnsupportedOperation:
+                    pass  # StringIO does not support detach
+                assert output.getvalue() == expected
+
+        # An empty string is the only test case for `preview=False`
+        output = io.StringIO()
+        io_TextIOWrapper = io.TextIOWrapper
+        with patch("io.TextIOWrapper", _new_wrapper(output, io_TextIOWrapper)):
+            try:
+                black.format_stdin_to_stdout(
+                    fast=True,
+                    content="",
+                    write_back=black.WriteBack.YES,
+                    mode=DEFAULT_MODE,
+                )
+            except io.UnsupportedOperation:
+                pass  # StringIO does not support detach
+            assert output.getvalue() == ""
+
+    def test_invalid_cli_regex(self) -> None:
+        for option in ["--include", "--exclude", "--extend-exclude", "--force-exclude"]:
+            self.invokeBlack(["-", option, "**()(!!*)"], exit_code=2)
+
+    def test_required_version_matches_version(self) -> None:
+        self.invokeBlack(
+            ["--required-version", black.__version__, "-c", "0"],
+            exit_code=0,
+            ignore_config=True,
+        )
+
+    def test_required_version_matches_partial_version(self) -> None:
+        self.invokeBlack(
+            ["--required-version", black.__version__.split(".")[0], "-c", "0"],
+            exit_code=0,
+            ignore_config=True,
+        )
+
+    def test_required_version_does_not_match_on_minor_version(self) -> None:
+        self.invokeBlack(
+            ["--required-version", black.__version__.split(".")[0] + ".999", "-c", "0"],
+            exit_code=1,
+            ignore_config=True,
+        )
+
+    def test_required_version_does_not_match_version(self) -> None:
+        result = BlackRunner().invoke(
+            black.main,
+            ["--required-version", "20.99b", "-c", "0"],
+        )
+        self.assertEqual(result.exit_code, 1)
+        self.assertIn("required version", result.stderr)
+
+    def test_preserves_line_endings(self) -> None:
+        with TemporaryDirectory() as workspace:
+            test_file = Path(workspace) / "test.py"
+            for nl in ["\n", "\r\n"]:
+                contents = nl.join(["def f(  ):", "    pass"])
+                test_file.write_bytes(contents.encode())
+                ff(test_file, write_back=black.WriteBack.YES)
+                updated_contents: bytes = test_file.read_bytes()
+                self.assertIn(nl.encode(), updated_contents)
+                if nl == "\n":
+                    self.assertNotIn(b"\r\n", updated_contents)
+
+    def test_preserves_line_endings_via_stdin(self) -> None:
+        for nl in ["\n", "\r\n"]:
+            contents = nl.join(["def f(  ):", "    pass"])
+            runner = BlackRunner()
+            result = runner.invoke(
+                black.main, ["-", "--fast"], input=BytesIO(contents.encode("utf-8"))
+            )
+            self.assertEqual(result.exit_code, 0)
+            output = result.stdout_bytes
+            self.assertIn(nl.encode("utf-8"), output)
+            if nl == "\n":
+                self.assertNotIn(b"\r\n", output)
+
+    def test_normalize_line_endings(self) -> None:
+        with TemporaryDirectory() as workspace:
+            test_file = Path(workspace) / "test.py"
+            for data, expected in (
+                (b"c\r\nc\n ", b"c\r\nc\r\n"),
+                (b"l\nl\r\n ", b"l\nl\n"),
+            ):
+                test_file.write_bytes(data)
+                ff(test_file, write_back=black.WriteBack.YES)
+                self.assertEqual(test_file.read_bytes(), expected)
+
+    def test_assert_equivalent_different_asts(self) -> None:
+        with self.assertRaises(AssertionError):
+            black.assert_equivalent("{}", "None")
+
+    def test_root_logger_not_used_directly(self) -> None:
+        def fail(*args: Any, **kwargs: Any) -> None:
+            self.fail("Record created with root logger")
+
+        with patch.multiple(
+            logging.root,
+            debug=fail,
+            info=fail,
+            warning=fail,
+            error=fail,
+            critical=fail,
+            log=fail,
+        ):
+            ff(THIS_DIR / "util.py")
+
+    def test_invalid_config_return_code(self) -> None:
+        tmp_file = Path(black.dump_to_file())
+        try:
+            tmp_config = Path(black.dump_to_file())
+            tmp_config.unlink()
+            args = ["--config", str(tmp_config), str(tmp_file)]
+            self.invokeBlack(args, exit_code=2, ignore_config=False)
+        finally:
+            tmp_file.unlink()
+
+    def test_parse_pyproject_toml(self) -> None:
+        test_toml_file = THIS_DIR / "test.toml"
+        config = black.parse_pyproject_toml(str(test_toml_file))
+        self.assertEqual(config["verbose"], 1)
+        self.assertEqual(config["check"], "no")
+        self.assertEqual(config["diff"], "y")
+        self.assertEqual(config["color"], True)
+        self.assertEqual(config["line_length"], 79)
+        self.assertEqual(config["target_version"], ["py36", "py37", "py38"])
+        self.assertEqual(config["python_cell_magics"], ["custom1", "custom2"])
+        self.assertEqual(config["exclude"], r"\.pyi?$")
+        self.assertEqual(config["include"], r"\.py?$")
+
+    def test_parse_pyproject_toml_project_metadata(self) -> None:
+        for test_toml, expected in [
+            ("only_black_pyproject.toml", ["py310"]),
+            ("only_metadata_pyproject.toml", ["py37", "py38", "py39", "py310"]),
+            ("neither_pyproject.toml", None),
+            ("both_pyproject.toml", ["py310"]),
+        ]:
+            test_toml_file = THIS_DIR / "data" / "project_metadata" / test_toml
+            config = black.parse_pyproject_toml(str(test_toml_file))
+            self.assertEqual(config.get("target_version"), expected)
+
+    def test_infer_target_version(self) -> None:
+        for version, expected in [
+            ("3.6", [TargetVersion.PY36]),
+            ("3.11.0rc1", [TargetVersion.PY311]),
+            (">=3.10", [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312]),
+            (
+                ">=3.10.6",
+                [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312],
+            ),
+            ("<3.6", [TargetVersion.PY33, TargetVersion.PY34, TargetVersion.PY35]),
+            (">3.7,<3.10", [TargetVersion.PY38, TargetVersion.PY39]),
+            (
+                ">3.7,!=3.8,!=3.9",
+                [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312],
+            ),
+            (
+                "> 3.9.4, != 3.10.3",
+                [
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            (
+                "!=3.3,!=3.4",
+                [
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            (
+                "==3.*",
+                [
+                    TargetVersion.PY33,
+                    TargetVersion.PY34,
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            ("==3.8.*", [TargetVersion.PY38]),
+            (None, None),
+            ("", None),
+            ("invalid", None),
+            ("==invalid", None),
+            (">3.9,!=invalid", None),
+            ("3", None),
+            ("3.2", None),
+            ("2.7.18", None),
+            ("==2.7", None),
+            (">3.10,<3.11", None),
+        ]:
+            test_toml = {"project": {"requires-python": version}}
+            result = black.files.infer_target_version(test_toml)
+            self.assertEqual(result, expected)
+
+    def test_read_pyproject_toml(self) -> None:
+        test_toml_file = THIS_DIR / "test.toml"
+        fake_ctx = FakeContext()
+        black.read_pyproject_toml(fake_ctx, FakeParameter(), str(test_toml_file))
+        config = fake_ctx.default_map
+        self.assertEqual(config["verbose"], "1")
+        self.assertEqual(config["check"], "no")
+        self.assertEqual(config["diff"], "y")
+        self.assertEqual(config["color"], "True")
+        self.assertEqual(config["line_length"], "79")
+        self.assertEqual(config["target_version"], ["py36", "py37", "py38"])
+        self.assertEqual(config["exclude"], r"\.pyi?$")
+        self.assertEqual(config["include"], r"\.py?$")
+
+    def test_read_pyproject_toml_from_stdin(self) -> None:
+        with TemporaryDirectory() as workspace:
+            root = Path(workspace)
+
+            src_dir = root / "src"
+            src_dir.mkdir()
+
+            src_pyproject = src_dir / "pyproject.toml"
+            src_pyproject.touch()
+
+            test_toml_content = (THIS_DIR / "test.toml").read_text(encoding="utf-8")
+            src_pyproject.write_text(test_toml_content, encoding="utf-8")
+
+            src_python = src_dir / "foo.py"
+            src_python.touch()
+
+            fake_ctx = FakeContext()
+            fake_ctx.params["src"] = ("-",)
+            fake_ctx.params["stdin_filename"] = str(src_python)
+
+            with change_directory(root):
+                black.read_pyproject_toml(fake_ctx, FakeParameter(), None)
+
+            config = fake_ctx.default_map
+            self.assertEqual(config["verbose"], "1")
+            self.assertEqual(config["check"], "no")
+            self.assertEqual(config["diff"], "y")
+            self.assertEqual(config["color"], "True")
+            self.assertEqual(config["line_length"], "79")
+            self.assertEqual(config["target_version"], ["py36", "py37", "py38"])
+            self.assertEqual(config["exclude"], r"\.pyi?$")
+            self.assertEqual(config["include"], r"\.py?$")
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_find_project_root(self) -> None:
+        with TemporaryDirectory() as workspace:
+            root = Path(workspace)
+            test_dir = root / "test"
+            test_dir.mkdir()
+
+            src_dir = root / "src"
+            src_dir.mkdir()
+
+            root_pyproject = root / "pyproject.toml"
+            root_pyproject.touch()
+            src_pyproject = src_dir / "pyproject.toml"
+            src_pyproject.touch()
+            src_python = src_dir / "foo.py"
+            src_python.touch()
+
+            self.assertEqual(
+                black.find_project_root((src_dir, test_dir)),
+                (root.resolve(), "pyproject.toml"),
+            )
+            self.assertEqual(
+                black.find_project_root((src_dir,)),
+                (src_dir.resolve(), "pyproject.toml"),
+            )
+            self.assertEqual(
+                black.find_project_root((src_python,)),
+                (src_dir.resolve(), "pyproject.toml"),
+            )
+
+            with change_directory(test_dir):
+                self.assertEqual(
+                    black.find_project_root(("-",), stdin_filename="../src/a.py"),
+                    (src_dir.resolve(), "pyproject.toml"),
+                )
+
+    @patch(
+        "black.files.find_user_pyproject_toml",
+    )
+    def test_find_pyproject_toml(self, find_user_pyproject_toml: MagicMock) -> None:
+        find_user_pyproject_toml.side_effect = RuntimeError()
+
+        with redirect_stderr(io.StringIO()) as stderr:
+            result = black.files.find_pyproject_toml(
+                path_search_start=(str(Path.cwd().root),)
+            )
+
+        assert result is None
+        err = stderr.getvalue()
+        assert "Ignoring user configuration" in err
+
+    @patch(
+        "black.files.find_user_pyproject_toml",
+        black.files.find_user_pyproject_toml.__wrapped__,
+    )
+    def test_find_user_pyproject_toml_linux(self) -> None:
+        if system() == "Windows":
+            return
+
+        # Test if XDG_CONFIG_HOME is checked
+        with TemporaryDirectory() as workspace:
+            tmp_user_config = Path(workspace) / "black"
+            with patch.dict("os.environ", {"XDG_CONFIG_HOME": workspace}):
+                self.assertEqual(
+                    black.files.find_user_pyproject_toml(), tmp_user_config.resolve()
+                )
+
+        # Test fallback for XDG_CONFIG_HOME
+        with patch.dict("os.environ"):
+            os.environ.pop("XDG_CONFIG_HOME", None)
+            fallback_user_config = Path("~/.config").expanduser() / "black"
+            self.assertEqual(
+                black.files.find_user_pyproject_toml(), fallback_user_config.resolve()
+            )
+
+    def test_find_user_pyproject_toml_windows(self) -> None:
+        if system() != "Windows":
+            return
+
+        user_config_path = Path.home() / ".black"
+        self.assertEqual(
+            black.files.find_user_pyproject_toml(), user_config_path.resolve()
+        )
+
+    def test_bpo_33660_workaround(self) -> None:
+        if system() == "Windows":
+            return
+
+        # https://bugs.python.org/issue33660
+        root = Path("/")
+        with change_directory(root):
+            path = Path("workspace") / "project"
+            report = black.Report(verbose=True)
+            normalized_path = black.normalize_path_maybe_ignore(path, root, report)
+            self.assertEqual(normalized_path, "workspace/project")
+
+    def test_normalize_path_ignore_windows_junctions_outside_of_root(self) -> None:
+        if system() != "Windows":
+            return
+
+        with TemporaryDirectory() as workspace:
+            root = Path(workspace)
+            junction_dir = root / "junction"
+            junction_target_outside_of_root = root / ".."
+            os.system(f"mklink /J {junction_dir} {junction_target_outside_of_root}")
+
+            report = black.Report(verbose=True)
+            normalized_path = black.normalize_path_maybe_ignore(
+                junction_dir, root, report
+            )
+            # Manually delete for Python < 3.8
+            os.system(f"rmdir {junction_dir}")
+
+            self.assertEqual(normalized_path, None)
+
+    def test_newline_comment_interaction(self) -> None:
+        source = "class A:\\\r\n# type: ignore\n pass\n"
+        output = black.format_str(source, mode=DEFAULT_MODE)
+        black.assert_stable(source, output, mode=DEFAULT_MODE)
+
+    def test_bpo_2142_workaround(self) -> None:
+        # https://bugs.python.org/issue2142
+
+        source, _ = read_data("miscellaneous", "missing_final_newline")
+        # read_data adds a trailing newline
+        source = source.rstrip()
+        expected, _ = read_data("miscellaneous", "missing_final_newline.diff")
+        tmp_file = Path(black.dump_to_file(source, ensure_final_newline=False))
+        diff_header = re.compile(
+            rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
+        )
+        try:
+            result = BlackRunner().invoke(black.main, ["--diff", str(tmp_file)])
+            self.assertEqual(result.exit_code, 0)
+        finally:
+            os.unlink(tmp_file)
+        actual = result.output
+        actual = diff_header.sub(DETERMINISTIC_HEADER, actual)
+        self.assertEqual(actual, expected)
+
+    @staticmethod
+    def compare_results(
+        result: click.testing.Result, expected_value: str, expected_exit_code: int
+    ) -> None:
+        """Helper method to test the value and exit code of a click Result."""
+        assert (
+            result.output == expected_value
+        ), "The output did not match the expected value."
+        assert result.exit_code == expected_exit_code, "The exit code is incorrect."
+
+    def test_code_option(self) -> None:
+        """Test the code option with no changes."""
+        code = 'print("Hello world")\n'
+        args = ["--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        self.compare_results(result, code, 0)
+
+    def test_code_option_changed(self) -> None:
+        """Test the code option when changes are required."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+        args = ["--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        self.compare_results(result, formatted, 0)
+
+    def test_code_option_check(self) -> None:
+        """Test the code option when check is passed."""
+        args = ["--check", "--code", 'print("Hello world")\n']
+        result = CliRunner().invoke(black.main, args)
+        self.compare_results(result, "", 0)
+
+    def test_code_option_check_changed(self) -> None:
+        """Test the code option when changes are required, and check is passed."""
+        args = ["--check", "--code", "print('hello world')"]
+        result = CliRunner().invoke(black.main, args)
+        self.compare_results(result, "", 1)
+
+    def test_code_option_diff(self) -> None:
+        """Test the code option when diff is passed."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+        result_diff = diff(code, formatted, "STDIN", "STDOUT")
+
+        args = ["--diff", "--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        # Remove time from diff
+        output = DIFF_TIME.sub("", result.output)
+
+        assert output == result_diff, "The output did not match the expected value."
+        assert result.exit_code == 0, "The exit code is incorrect."
+
+    def test_code_option_color_diff(self) -> None:
+        """Test the code option when color and diff are passed."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+        result_diff = diff(code, formatted, "STDIN", "STDOUT")
+        result_diff = color_diff(result_diff)
+
+        args = ["--diff", "--color", "--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        # Remove time from diff
+        output = DIFF_TIME.sub("", result.output)
+
+        assert output == result_diff, "The output did not match the expected value."
+        assert result.exit_code == 0, "The exit code is incorrect."
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_code_option_safe(self) -> None:
+        """Test that the code option throws an error when the sanity checks fail."""
+        # Patch black.assert_equivalent to ensure the sanity checks fail
+        with patch.object(black, "assert_equivalent", side_effect=AssertionError):
+            code = 'print("Hello world")'
+            error_msg = f"{code}\nerror: cannot format <string>: \n"
+
+            args = ["--safe", "--code", code]
+            result = CliRunner().invoke(black.main, args)
+
+            self.compare_results(result, error_msg, 123)
+
+    def test_code_option_fast(self) -> None:
+        """Test that the code option ignores errors when the sanity checks fail."""
+        # Patch black.assert_equivalent to ensure the sanity checks fail
+        with patch.object(black, "assert_equivalent", side_effect=AssertionError):
+            code = 'print("Hello world")'
+            formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+            args = ["--fast", "--code", code]
+            result = CliRunner().invoke(black.main, args)
+
+            self.compare_results(result, formatted, 0)
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_code_option_config(self) -> None:
+        """
+        Test that the code option finds the pyproject.toml in the current directory.
+        """
+        with patch.object(black, "parse_pyproject_toml", return_value={}) as parse:
+            args = ["--code", "print"]
+            # This is the only directory known to contain a pyproject.toml
+            with change_directory(PROJECT_ROOT):
+                CliRunner().invoke(black.main, args)
+                pyproject_path = Path(Path.cwd(), "pyproject.toml").resolve()
+
+            assert (
+                len(parse.mock_calls) >= 1
+            ), "Expected config parse to be called with the current directory."
+
+            _, call_args, _ = parse.mock_calls[0]
+            assert (
+                call_args[0].lower() == str(pyproject_path).lower()
+            ), "Incorrect config loaded."
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_code_option_parent_config(self) -> None:
+        """
+        Test that the code option finds the pyproject.toml in the parent directory.
+        """
+        with patch.object(black, "parse_pyproject_toml", return_value={}) as parse:
+            with change_directory(THIS_DIR):
+                args = ["--code", "print"]
+                CliRunner().invoke(black.main, args)
+
+                pyproject_path = Path(Path().cwd().parent, "pyproject.toml").resolve()
+                assert (
+                    len(parse.mock_calls) >= 1
+                ), "Expected config parse to be called with the current directory."
+
+                _, call_args, _ = parse.mock_calls[0]
+                assert (
+                    call_args[0].lower() == str(pyproject_path).lower()
+                ), "Incorrect config loaded."
+
+    def test_for_handled_unexpected_eof_error(self) -> None:
+        """
+        Test that an unexpected EOF SyntaxError is nicely presented.
+        """
+        with pytest.raises(black.parsing.InvalidInput) as exc_info:
+            black.lib2to3_parse("print(", {})
+
+        exc_info.match("Cannot parse: 2:0: EOF in multi-line statement")
+
+    def test_equivalency_ast_parse_failure_includes_error(self) -> None:
+        with pytest.raises(AssertionError) as err:
+            black.assert_equivalent("a«»a  = 1", "a«»a  = 1")
+
+        err.match("--safe")
+        # Unfortunately the SyntaxError message has changed in newer versions so we
+        # can't match it directly.
+        err.match("invalid character")
+        err.match(r"\(<unknown>, line 1\)")
+
+
+class TestCaching:
+    def test_get_cache_dir(
+        self,
+        tmp_path: Path,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        # Create multiple cache directories
+        workspace1 = tmp_path / "ws1"
+        workspace1.mkdir()
+        workspace2 = tmp_path / "ws2"
+        workspace2.mkdir()
+
+        # Force user_cache_dir to use the temporary directory for easier assertions
+        patch_user_cache_dir = patch(
+            target="black.cache.user_cache_dir",
+            autospec=True,
+            return_value=str(workspace1),
+        )
+
+        # If BLACK_CACHE_DIR is not set, use user_cache_dir
+        monkeypatch.delenv("BLACK_CACHE_DIR", raising=False)
+        with patch_user_cache_dir:
+            assert get_cache_dir() == workspace1
+
+        # If it is set, use the path provided in the env var.
+        monkeypatch.setenv("BLACK_CACHE_DIR", str(workspace2))
+        assert get_cache_dir() == workspace2
+
+    def test_cache_broken_file(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace:
+            cache_file = get_cache_file(mode)
+            cache_file.write_text("this is not a pickle", encoding="utf-8")
+            assert black.read_cache(mode) == {}
+            src = (workspace / "test.py").resolve()
+            src.write_text("print('hello')", encoding="utf-8")
+            invokeBlack([str(src)])
+            cache = black.read_cache(mode)
+            assert str(src) in cache
+
+    def test_cache_single_file_already_cached(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace:
+            src = (workspace / "test.py").resolve()
+            src.write_text("print('hello')", encoding="utf-8")
+            black.write_cache({}, [src], mode)
+            invokeBlack([str(src)])
+            assert src.read_text(encoding="utf-8") == "print('hello')"
+
+    @event_loop()
+    def test_cache_multiple_files(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace, patch(
+            "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
+        ):
+            one = (workspace / "one.py").resolve()
+            one.write_text("print('hello')", encoding="utf-8")
+            two = (workspace / "two.py").resolve()
+            two.write_text("print('hello')", encoding="utf-8")
+            black.write_cache({}, [one], mode)
+            invokeBlack([str(workspace)])
+            assert one.read_text(encoding="utf-8") == "print('hello')"
+            assert two.read_text(encoding="utf-8") == 'print("hello")\n'
+            cache = black.read_cache(mode)
+            assert str(one) in cache
+            assert str(two) in cache
+
+    @pytest.mark.parametrize("color", [False, True], ids=["no-color", "with-color"])
+    def test_no_cache_when_writeback_diff(self, color: bool) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace:
+            src = (workspace / "test.py").resolve()
+            src.write_text("print('hello')", encoding="utf-8")
+            with patch("black.read_cache") as read_cache, patch(
+                "black.write_cache"
+            ) as write_cache:
+                cmd = [str(src), "--diff"]
+                if color:
+                    cmd.append("--color")
+                invokeBlack(cmd)
+                cache_file = get_cache_file(mode)
+                assert cache_file.exists() is False
+                write_cache.assert_not_called()
+                read_cache.assert_not_called()
+
+    @pytest.mark.parametrize("color", [False, True], ids=["no-color", "with-color"])
+    @event_loop()
+    def test_output_locking_when_writeback_diff(self, color: bool) -> None:
+        with cache_dir() as workspace:
+            for tag in range(0, 4):
+                src = (workspace / f"test{tag}.py").resolve()
+                src.write_text("print('hello')", encoding="utf-8")
+            with patch(
+                "black.concurrency.Manager", wraps=multiprocessing.Manager
+            ) as mgr:
+                cmd = ["--diff", str(workspace)]
+                if color:
+                    cmd.append("--color")
+                invokeBlack(cmd, exit_code=0)
+                # this isn't quite doing what we want, but if it _isn't_
+                # called then we cannot be using the lock it provides
+                mgr.assert_called()
+
+    def test_no_cache_when_stdin(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir():
+            result = CliRunner().invoke(
+                black.main, ["-"], input=BytesIO(b"print('hello')")
+            )
+            assert not result.exit_code
+            cache_file = get_cache_file(mode)
+            assert not cache_file.exists()
+
+    def test_read_cache_no_cachefile(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir():
+            assert black.read_cache(mode) == {}
+
+    def test_write_cache_read_cache(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace:
+            src = (workspace / "test.py").resolve()
+            src.touch()
+            black.write_cache({}, [src], mode)
+            cache = black.read_cache(mode)
+            assert str(src) in cache
+            assert cache[str(src)] == black.get_cache_info(src)
+
+    def test_filter_cached(self) -> None:
+        with TemporaryDirectory() as workspace:
+            path = Path(workspace)
+            uncached = (path / "uncached").resolve()
+            cached = (path / "cached").resolve()
+            cached_but_changed = (path / "changed").resolve()
+            uncached.touch()
+            cached.touch()
+            cached_but_changed.touch()
+            cache = {
+                str(cached): black.get_cache_info(cached),
+                str(cached_but_changed): (0.0, 0),
+            }
+            todo, done = black.cache.filter_cached(
+                cache, {uncached, cached, cached_but_changed}
+            )
+            assert todo == {uncached, cached_but_changed}
+            assert done == {cached}
+
+    def test_write_cache_creates_directory_if_needed(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir(exists=False) as workspace:
+            assert not workspace.exists()
+            black.write_cache({}, [], mode)
+            assert workspace.exists()
+
+    @event_loop()
+    def test_failed_formatting_does_not_get_cached(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace, patch(
+            "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
+        ):
+            failing = (workspace / "failing.py").resolve()
+            failing.write_text("not actually python", encoding="utf-8")
+            clean = (workspace / "clean.py").resolve()
+            clean.write_text('print("hello")\n', encoding="utf-8")
+            invokeBlack([str(workspace)], exit_code=123)
+            cache = black.read_cache(mode)
+            assert str(failing) not in cache
+            assert str(clean) in cache
+
+    def test_write_cache_write_fail(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir(), patch.object(Path, "open") as mock:
+            mock.side_effect = OSError
+            black.write_cache({}, [], mode)
+
+    def test_read_cache_line_lengths(self) -> None:
+        mode = DEFAULT_MODE
+        short_mode = replace(DEFAULT_MODE, line_length=1)
+        with cache_dir() as workspace:
+            path = (workspace / "file.py").resolve()
+            path.touch()
+            black.write_cache({}, [path], mode)
+            one = black.read_cache(mode)
+            assert str(path) in one
+            two = black.read_cache(short_mode)
+            assert str(path) not in two
+
+
+def assert_collected_sources(
+    src: Sequence[Union[str, Path]],
+    expected: Sequence[Union[str, Path]],
+    *,
+    ctx: Optional[FakeContext] = None,
+    exclude: Optional[str] = None,
+    include: Optional[str] = None,
+    extend_exclude: Optional[str] = None,
+    force_exclude: Optional[str] = None,
+    stdin_filename: Optional[str] = None,
+) -> None:
+    gs_src = tuple(str(Path(s)) for s in src)
+    gs_expected = [Path(s) for s in expected]
+    gs_exclude = None if exclude is None else compile_pattern(exclude)
+    gs_include = DEFAULT_INCLUDE if include is None else compile_pattern(include)
+    gs_extend_exclude = (
+        None if extend_exclude is None else compile_pattern(extend_exclude)
+    )
+    gs_force_exclude = None if force_exclude is None else compile_pattern(force_exclude)
+    collected = black.get_sources(
+        ctx=ctx or FakeContext(),
+        src=gs_src,
+        quiet=False,
+        verbose=False,
+        include=gs_include,
+        exclude=gs_exclude,
+        extend_exclude=gs_extend_exclude,
+        force_exclude=gs_force_exclude,
+        report=black.Report(),
+        stdin_filename=stdin_filename,
+    )
+    assert sorted(collected) == sorted(gs_expected)
+
+
+class TestFileCollection:
     def test_include_exclude(self) -> None:
-        path = THIS_DIR / "include_exclude_tests"
+        path = THIS_DIR / "data" / "include_exclude_tests"
+        src = [path]
+        expected = [
+            Path(path / "b/dont_exclude/a.py"),
+            Path(path / "b/dont_exclude/a.pyi"),
+        ]
+        assert_collected_sources(
+            src,
+            expected,
+            include=r"\.pyi?$",
+            exclude=r"/exclude/|/\.definitely_exclude/",
+        )
+
+    def test_gitignore_used_as_default(self) -> None:
+        base = Path(DATA_DIR / "include_exclude_tests")
+        expected = [
+            base / "b/.definitely_exclude/a.py",
+            base / "b/.definitely_exclude/a.pyi",
+        ]
+        src = [base / "b/"]
+        ctx = FakeContext()
+        ctx.obj["root"] = base
+        assert_collected_sources(src, expected, ctx=ctx, extend_exclude=r"/exclude/")
+
+    def test_gitignore_used_on_multiple_sources(self) -> None:
+        root = Path(DATA_DIR / "gitignore_used_on_multiple_sources")
+        expected = [
+            root / "dir1" / "b.py",
+            root / "dir2" / "b.py",
+        ]
+        ctx = FakeContext()
+        ctx.obj["root"] = root
+        src = [root / "dir1", root / "dir2"]
+        assert_collected_sources(src, expected, ctx=ctx)
+
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_exclude_for_issue_1572(self) -> None:
+        # Exclude shouldn't touch files that were explicitly given to Black through the
+        # CLI. Exclude is supposed to only apply to the recursive discovery of files.
+        # https://github.com/psf/black/issues/1572
+        path = DATA_DIR / "include_exclude_tests"
+        src = [path / "b/exclude/a.py"]
+        expected = [path / "b/exclude/a.py"]
+        assert_collected_sources(src, expected, include="", exclude=r"/exclude/|a\.py")
+
+    def test_gitignore_exclude(self) -> None:
+        path = THIS_DIR / "data" / "include_exclude_tests"
         include = re.compile(r"\.pyi?$")
-        exclude = re.compile(r"/exclude/|/\.definitely_exclude/")
+        exclude = re.compile(r"")
+        report = black.Report()
+        gitignore = PathSpec.from_lines(
+            "gitwildmatch", ["exclude/", ".definitely_exclude"]
+        )
         sources: List[Path] = []
         expected = [
-            Path(THIS_DIR / "include_exclude_tests/b/dont_exclude/a.py"),
-            Path(THIS_DIR / "include_exclude_tests/b/dont_exclude/a.pyi"),
+            Path(path / "b/dont_exclude/a.py"),
+            Path(path / "b/dont_exclude/a.pyi"),
         ]
         this_abs = THIS_DIR.resolve()
-        sources.extend(black.gen_python_files_in_dir(path, this_abs, include, exclude))
-        self.assertEqual(sorted(expected), sorted(sources))
+        sources.extend(
+            black.gen_python_files(
+                path.iterdir(),
+                this_abs,
+                include,
+                exclude,
+                None,
+                None,
+                report,
+                {path: gitignore},
+                verbose=False,
+                quiet=False,
+            )
+        )
+        assert sorted(expected) == sorted(sources)
+
+    def test_nested_gitignore(self) -> None:
+        path = Path(THIS_DIR / "data" / "nested_gitignore_tests")
+        include = re.compile(r"\.pyi?$")
+        exclude = re.compile(r"")
+        root_gitignore = black.files.get_gitignore(path)
+        report = black.Report()
+        expected: List[Path] = [
+            Path(path / "x.py"),
+            Path(path / "root/b.py"),
+            Path(path / "root/c.py"),
+            Path(path / "root/child/c.py"),
+        ]
+        this_abs = THIS_DIR.resolve()
+        sources = list(
+            black.gen_python_files(
+                path.iterdir(),
+                this_abs,
+                include,
+                exclude,
+                None,
+                None,
+                report,
+                {path: root_gitignore},
+                verbose=False,
+                quiet=False,
+            )
+        )
+        assert sorted(expected) == sorted(sources)
+
+    def test_nested_gitignore_directly_in_source_directory(self) -> None:
+        # https://github.com/psf/black/issues/2598
+        path = Path(DATA_DIR / "nested_gitignore_tests")
+        src = Path(path / "root" / "child")
+        expected = [src / "a.py", src / "c.py"]
+        assert_collected_sources([src], expected)
+
+    def test_invalid_gitignore(self) -> None:
+        path = THIS_DIR / "data" / "invalid_gitignore_tests"
+        empty_config = path / "pyproject.toml"
+        result = BlackRunner().invoke(
+            black.main, ["--verbose", "--config", str(empty_config), str(path)]
+        )
+        assert result.exit_code == 1
+        assert result.stderr_bytes is not None
+
+        gitignore = path / ".gitignore"
+        assert f"Could not parse {gitignore}" in result.stderr_bytes.decode()
+
+    def test_invalid_nested_gitignore(self) -> None:
+        path = THIS_DIR / "data" / "invalid_nested_gitignore_tests"
+        empty_config = path / "pyproject.toml"
+        result = BlackRunner().invoke(
+            black.main, ["--verbose", "--config", str(empty_config), str(path)]
+        )
+        assert result.exit_code == 1
+        assert result.stderr_bytes is not None
+
+        gitignore = path / "a" / ".gitignore"
+        assert f"Could not parse {gitignore}" in result.stderr_bytes.decode()
+
+    def test_gitignore_that_ignores_subfolders(self) -> None:
+        # If gitignore with */* is in root
+        root = Path(DATA_DIR / "ignore_subfolders_gitignore_tests" / "subdir")
+        expected = [root / "b.py"]
+        ctx = FakeContext()
+        ctx.obj["root"] = root
+        assert_collected_sources([root], expected, ctx=ctx)
+
+        # If .gitignore with */* is nested
+        root = Path(DATA_DIR / "ignore_subfolders_gitignore_tests")
+        expected = [
+            root / "a.py",
+            root / "subdir" / "b.py",
+        ]
+        ctx = FakeContext()
+        ctx.obj["root"] = root
+        assert_collected_sources([root], expected, ctx=ctx)
+
+        # If command is executed from outer dir
+        root = Path(DATA_DIR / "ignore_subfolders_gitignore_tests")
+        target = root / "subdir"
+        expected = [target / "b.py"]
+        ctx = FakeContext()
+        ctx.obj["root"] = root
+        assert_collected_sources([target], expected, ctx=ctx)
 
     def test_empty_include(self) -> None:
-        path = THIS_DIR / "include_exclude_tests"
-        empty = re.compile(r"")
-        sources: List[Path] = []
+        path = DATA_DIR / "include_exclude_tests"
+        src = [path]
         expected = [
             Path(path / "b/exclude/a.pie"),
             Path(path / "b/exclude/a.py"),
@@ -882,40 +2316,148 @@ class BlackTestCase(unittest.TestCase):
             Path(path / "b/.definitely_exclude/a.pie"),
             Path(path / "b/.definitely_exclude/a.py"),
             Path(path / "b/.definitely_exclude/a.pyi"),
+            Path(path / ".gitignore"),
+            Path(path / "pyproject.toml"),
         ]
-        this_abs = THIS_DIR.resolve()
-        sources.extend(
-            black.gen_python_files_in_dir(
-                path, this_abs, empty, re.compile(black.DEFAULT_EXCLUDES)
-            )
-        )
-        self.assertEqual(sorted(expected), sorted(sources))
+        # Setting exclude explicitly to an empty string to block .gitignore usage.
+        assert_collected_sources(src, expected, include="", exclude="")
 
-    def test_empty_exclude(self) -> None:
-        path = THIS_DIR / "include_exclude_tests"
-        empty = re.compile(r"")
-        sources: List[Path] = []
+    def test_extend_exclude(self) -> None:
+        path = DATA_DIR / "include_exclude_tests"
+        src = [path]
         expected = [
-            Path(path / "b/dont_exclude/a.py"),
-            Path(path / "b/dont_exclude/a.pyi"),
             Path(path / "b/exclude/a.py"),
-            Path(path / "b/exclude/a.pyi"),
-            Path(path / "b/.definitely_exclude/a.py"),
-            Path(path / "b/.definitely_exclude/a.pyi"),
+            Path(path / "b/dont_exclude/a.py"),
         ]
-        this_abs = THIS_DIR.resolve()
-        sources.extend(
-            black.gen_python_files_in_dir(
-                path, this_abs, re.compile(black.DEFAULT_INCLUDES), empty
+        assert_collected_sources(
+            src, expected, exclude=r"\.pyi$", extend_exclude=r"\.definitely_exclude"
+        )
+
+    @pytest.mark.incompatible_with_mypyc
+    def test_symlink_out_of_root_directory(self) -> None:
+        path = MagicMock()
+        root = THIS_DIR.resolve()
+        child = MagicMock()
+        include = re.compile(black.DEFAULT_INCLUDES)
+        exclude = re.compile(black.DEFAULT_EXCLUDES)
+        report = black.Report()
+        gitignore = PathSpec.from_lines("gitwildmatch", [])
+        # `child` should behave like a symlink which resolved path is clearly
+        # outside of the `root` directory.
+        path.iterdir.return_value = [child]
+        child.resolve.return_value = Path("/a/b/c")
+        child.as_posix.return_value = "/a/b/c"
+        try:
+            list(
+                black.gen_python_files(
+                    path.iterdir(),
+                    root,
+                    include,
+                    exclude,
+                    None,
+                    None,
+                    report,
+                    {path: gitignore},
+                    verbose=False,
+                    quiet=False,
+                )
             )
+        except ValueError as ve:
+            pytest.fail(f"`get_python_files_in_dir()` failed: {ve}")
+        path.iterdir.assert_called_once()
+        child.resolve.assert_called_once()
+
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_get_sources_with_stdin(self) -> None:
+        src = ["-"]
+        expected = ["-"]
+        assert_collected_sources(src, expected, include="", exclude=r"/exclude/|a\.py")
+
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_get_sources_with_stdin_filename(self) -> None:
+        src = ["-"]
+        stdin_filename = str(THIS_DIR / "data/collections.py")
+        expected = [f"__BLACK_STDIN_FILENAME__{stdin_filename}"]
+        assert_collected_sources(
+            src,
+            expected,
+            exclude=r"/exclude/a\.py",
+            stdin_filename=stdin_filename,
         )
-        self.assertEqual(sorted(expected), sorted(sources))
 
-    def test_invalid_include_exclude(self) -> None:
-        for option in ["--include", "--exclude"]:
-            result = CliRunner().invoke(black.main, ["-", option, "**()(!!*)"])
-            self.assertEqual(result.exit_code, 2)
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_get_sources_with_stdin_filename_and_exclude(self) -> None:
+        # Exclude shouldn't exclude stdin_filename since it is mimicking the
+        # file being passed directly. This is the same as
+        # test_exclude_for_issue_1572
+        path = DATA_DIR / "include_exclude_tests"
+        src = ["-"]
+        stdin_filename = str(path / "b/exclude/a.py")
+        expected = [f"__BLACK_STDIN_FILENAME__{stdin_filename}"]
+        assert_collected_sources(
+            src,
+            expected,
+            exclude=r"/exclude/|a\.py",
+            stdin_filename=stdin_filename,
+        )
+
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_get_sources_with_stdin_filename_and_extend_exclude(self) -> None:
+        # Extend exclude shouldn't exclude stdin_filename since it is mimicking the
+        # file being passed directly. This is the same as
+        # test_exclude_for_issue_1572
+        src = ["-"]
+        path = THIS_DIR / "data" / "include_exclude_tests"
+        stdin_filename = str(path / "b/exclude/a.py")
+        expected = [f"__BLACK_STDIN_FILENAME__{stdin_filename}"]
+        assert_collected_sources(
+            src,
+            expected,
+            extend_exclude=r"/exclude/|a\.py",
+            stdin_filename=stdin_filename,
+        )
+
+    @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
+    def test_get_sources_with_stdin_filename_and_force_exclude(self) -> None:
+        # Force exclude should exclude the file when passing it through
+        # stdin_filename
+        path = THIS_DIR / "data" / "include_exclude_tests"
+        stdin_filename = str(path / "b/exclude/a.py")
+        assert_collected_sources(
+            src=["-"],
+            expected=[],
+            force_exclude=r"/exclude/|a\.py",
+            stdin_filename=stdin_filename,
+        )
 
 
-if __name__ == "__main__":
-    unittest.main()
+try:
+    with open(black.__file__, "r", encoding="utf-8") as _bf:
+        black_source_lines = _bf.readlines()
+except UnicodeDecodeError:
+    if not black.COMPILED:
+        raise
+
+
+def tracefunc(
+    frame: types.FrameType, event: str, arg: Any
+) -> Callable[[types.FrameType, str, Any], Any]:
+    """Show function calls `from black/__init__.py` as they happen.
+
+    Register this with `sys.settrace()` in a test you're debugging.
+    """
+    if event != "call":
+        return tracefunc
+
+    stack = len(inspect.stack()) - 19
+    stack *= 2
+    filename = frame.f_code.co_filename
+    lineno = frame.f_lineno
+    func_sig_lineno = lineno - 1
+    funcname = black_source_lines[func_sig_lineno].strip()
+    while funcname.startswith("@"):
+        func_sig_lineno += 1
+        funcname = black_source_lines[func_sig_lineno].strip()
+    if "black/__init__.py" in filename:
+        print(f"{' ' * stack}{lineno}:{funcname}")
+    return tracefunc