X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/cbf5401efff0524f7395c5fb81551de75b17c89e..4bee9cca5553c55493203822b5a112ec5216bc74:/tests/test_black.py

diff --git a/tests/test_black.py b/tests/test_black.py
index 5647a00..dda1055 100644
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -6,11 +6,12 @@ import io
 import logging
 import multiprocessing
 import os
+import re
 import sys
 import types
 import unittest
 from concurrent.futures import ThreadPoolExecutor
-from contextlib import contextmanager
+from contextlib import contextmanager, redirect_stderr
 from dataclasses import replace
 from io import BytesIO
 from pathlib import Path
@@ -24,6 +25,7 @@ from typing import (
     List,
     Optional,
     Sequence,
+    Type,
     TypeVar,
     Union,
 )
@@ -31,7 +33,6 @@ from unittest.mock import MagicMock, patch
 
 import click
 import pytest
-import regex as re
 from click import unstyle
 from click.testing import CliRunner
 from pathspec import PathSpec
@@ -40,7 +41,7 @@ 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_file
+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
@@ -59,10 +60,13 @@ from tests.util import (
     dump_to_stderr,
     ff,
     fs,
+    get_case_path,
     read_data,
+    read_data_from_file,
 )
 
 THIS_FILE = Path(__file__)
+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)
@@ -70,7 +74,7 @@ T = TypeVar("T")
 R = TypeVar("R")
 
 # Match the time output in a diff, but nothing else
-DIFF_TIME = re.compile(r"\t[\d-:+\. ]+")
+DIFF_TIME = re.compile(r"\t[\d\-:+\. ]+")
 
 
 @contextmanager
@@ -100,6 +104,8 @@ class FakeContext(click.Context):
 
     def __init__(self) -> None:
         self.default_map: Dict[str, Any] = {}
+        # Dummy root, since most of the tests don't care about it
+        self.obj: Dict[str, Any] = {"root": PROJECT_ROOT}
 
 
 class FakeParameter(click.Parameter):
@@ -122,7 +128,7 @@ def invokeBlack(
     runner = BlackRunner()
     if ignore_config:
         args = ["--verbose", "--config", str(THIS_DIR / "empty.toml"), *args]
-    result = runner.invoke(black.main, 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 = (
@@ -148,11 +154,49 @@ class BlackTestCase(BlackBaseTestCase):
             os.unlink(tmp_file)
         self.assertFormatEqual(expected, actual)
 
+    @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("utf8")
+            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("src/black/__init__", data=False)
+        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}"],
+            [
+                "-",
+                "--fast",
+                f"--line-length={black.DEFAULT_LINE_LENGTH}",
+                f"--config={EMPTY_CONFIG}",
+            ],
             input=BytesIO(source.encode("utf8")),
         )
         self.assertEqual(result.exit_code, 0)
@@ -166,15 +210,14 @@ class BlackTestCase(BlackBaseTestCase):
             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("expression.py")
-        expected, _ = read_data("expression.diff")
-        config = THIS_DIR / "data" / "empty_pyproject.toml"
+        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={config}",
+            f"--config={EMPTY_CONFIG}",
         ]
         result = BlackRunner().invoke(
             black.main, args, input=BytesIO(source.encode("utf8"))
@@ -185,22 +228,21 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertEqual(expected, actual)
 
     def test_piping_diff_with_color(self) -> None:
-        source, _ = read_data("expression.py")
-        config = THIS_DIR / "data" / "empty_pyproject.toml"
+        source, _ = read_data("simple_cases", "expression.py")
         args = [
             "-",
             "--fast",
             f"--line-length={black.DEFAULT_LINE_LENGTH}",
             "--diff",
             "--color",
-            f"--config={config}",
+            f"--config={EMPTY_CONFIG}",
         ]
         result = BlackRunner().invoke(
             black.main, args, input=BytesIO(source.encode("utf8"))
         )
         actual = result.output
         # Again, the contents are checked in a different test, so only look for colors.
-        self.assertIn("\033[1;37m", actual)
+        self.assertIn("\033[1m", actual)
         self.assertIn("\033[36m", actual)
         self.assertIn("\033[32m", actual)
         self.assertIn("\033[31m", actual)
@@ -208,7 +250,7 @@ class BlackTestCase(BlackBaseTestCase):
 
     @patch("black.dump_to_file", dump_to_stderr)
     def _test_wip(self) -> None:
-        source, expected = read_data("wip")
+        source, expected = read_data("miscellaneous", "wip")
         sys.settrace(tracefunc)
         mode = replace(
             DEFAULT_MODE,
@@ -221,47 +263,8 @@ class BlackTestCase(BlackBaseTestCase):
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, black.FileMode())
 
-    @unittest.expectedFailure
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability1(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens1")
-        actual = fs(source)
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
-    @unittest.expectedFailure
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability2(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens2")
-        actual = fs(source)
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
-    @unittest.expectedFailure
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability3(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens3")
-        actual = fs(source)
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability1_pass2(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens1")
-        actual = fs(fs(source))  # this is what `format_file_contents` does with --safe
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability2_pass2(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens2")
-        actual = fs(fs(source))  # this is what `format_file_contents` does with --safe
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
-    @patch("black.dump_to_file", dump_to_stderr)
-    def test_trailing_comma_optional_parens_stability3_pass2(self) -> None:
-        source, _expected = read_data("trailing_comma_optional_parens3")
-        actual = fs(fs(source))  # this is what `format_file_contents` does with --safe
-        black.assert_stable(source, actual, DEFAULT_MODE)
-
     def test_pep_572_version_detection(self) -> None:
-        source, _ = read_data("pep_572")
+        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)
@@ -269,7 +272,7 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertIn(black.TargetVersion.PY38, 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))
@@ -283,9 +286,8 @@ class BlackTestCase(BlackBaseTestCase):
             black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_expression_diff(self) -> None:
-        source, _ = read_data("expression.py")
-        config = THIS_DIR / "data" / "empty_pyproject.toml"
-        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))
         diff_header = re.compile(
             rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
@@ -293,7 +295,7 @@ class BlackTestCase(BlackBaseTestCase):
         )
         try:
             result = BlackRunner().invoke(
-                black.main, ["--diff", str(tmp_file), f"--config={config}"]
+                black.main, ["--diff", str(tmp_file), f"--config={EMPTY_CONFIG}"]
             )
             self.assertEqual(result.exit_code, 0)
         finally:
@@ -310,37 +312,57 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(expected, actual, msg)
 
     def test_expression_diff_with_color(self) -> None:
-        source, _ = read_data("expression.py")
-        config = THIS_DIR / "data" / "empty_pyproject.toml"
-        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))
         try:
             result = BlackRunner().invoke(
-                black.main, ["--diff", "--color", str(tmp_file), f"--config={config}"]
+                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[1;37m", actual)
+        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("pep_570")
+        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")
-        mode = black.Mode(experimental_string_processing=True)
+        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)
@@ -348,16 +370,44 @@ class BlackTestCase(BlackBaseTestCase):
         black.assert_equivalent(source, not_normalized)
         black.assert_stable(source, not_normalized, mode=mode)
 
+    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)
+        with open(tmp_file, encoding="utf8") as f:
+            actual = f.read()
+        self.assertFormatEqual(source, actual)
+
+    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("expression.py")
-        expected, _ = read_data("expression_skip_magic_trailing_comma.diff")
+        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)])
+            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)
@@ -375,8 +425,8 @@ class BlackTestCase(BlackBaseTestCase):
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_async_as_identifier(self) -> None:
-        source_path = (THIS_DIR / "data" / "async_as_identifier.py").resolve()
-        source, expected = read_data("async_as_identifier")
+        source_path = get_case_path("miscellaneous", "async_as_identifier")
+        source, expected = read_data_from_file(source_path)
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         major, minor = sys.version_info[:2]
@@ -390,8 +440,8 @@ class BlackTestCase(BlackBaseTestCase):
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_python37(self) -> None:
-        source_path = (THIS_DIR / "data" / "python37.py").resolve()
-        source, expected = read_data("python37")
+        source_path = get_case_path("py_37", "python37")
+        source, expected = read_data_from_file(source_path)
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         major, minor = sys.version_info[:2]
@@ -469,8 +519,10 @@ class BlackTestCase(BlackBaseTestCase):
             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)
@@ -479,8 +531,10 @@ class BlackTestCase(BlackBaseTestCase):
             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")
@@ -489,8 +543,10 @@ class BlackTestCase(BlackBaseTestCase):
             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.path_ignored(Path("wat"), "no match")
@@ -499,8 +555,10 @@ class BlackTestCase(BlackBaseTestCase):
             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.",
+                (
+                    "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)
@@ -509,22 +567,28 @@ class BlackTestCase(BlackBaseTestCase):
             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.",
+                (
+                    "2 files would be reformatted, 3 files would be left unchanged, 2"
+                    " files would fail to reformat."
+                ),
             )
 
     def test_report_quiet(self) -> None:
@@ -566,8 +630,10 @@ class BlackTestCase(BlackBaseTestCase):
             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)
@@ -575,8 +641,10 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(len(err_lines), 1)
             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")
@@ -585,8 +653,10 @@ class BlackTestCase(BlackBaseTestCase):
             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.path_ignored(Path("wat"), "no match")
@@ -594,8 +664,10 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(len(err_lines), 2)
             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)
@@ -603,22 +675,28 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(len(err_lines), 2)
             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.",
+                (
+                    "2 files would be reformatted, 3 files would be left unchanged, 2"
+                    " files would fail to reformat."
+                ),
             )
 
     def test_report_normal(self) -> None:
@@ -662,8 +740,10 @@ class BlackTestCase(BlackBaseTestCase):
             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)
@@ -672,8 +752,10 @@ class BlackTestCase(BlackBaseTestCase):
             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")
@@ -682,8 +764,10 @@ class BlackTestCase(BlackBaseTestCase):
             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.path_ignored(Path("wat"), "no match")
@@ -691,8 +775,10 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(len(err_lines), 2)
             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)
@@ -700,22 +786,28 @@ class BlackTestCase(BlackBaseTestCase):
             self.assertEqual(len(err_lines), 2)
             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.",
+                (
+                    "2 files would be reformatted, 3 files would be left unchanged, 2"
+                    " files would fail to reformat."
+                ),
             )
 
     def test_lib2to3_parse(self) -> None:
@@ -724,31 +816,22 @@ class BlackTestCase(BlackBaseTestCase):
 
         straddling = "x + y"
         black.lib2to3_parse(straddling)
-        black.lib2to3_parse(straddling, {TargetVersion.PY27})
         black.lib2to3_parse(straddling, {TargetVersion.PY36})
-        black.lib2to3_parse(straddling, {TargetVersion.PY27, TargetVersion.PY36})
 
         py2_only = "print x"
-        black.lib2to3_parse(py2_only)
-        black.lib2to3_parse(py2_only, {TargetVersion.PY27})
         with self.assertRaises(black.InvalidInput):
             black.lib2to3_parse(py2_only, {TargetVersion.PY36})
-        with self.assertRaises(black.InvalidInput):
-            black.lib2to3_parse(py2_only, {TargetVersion.PY27, TargetVersion.PY36})
 
         py3_only = "exec(x, end=y)"
         black.lib2to3_parse(py3_only)
-        with self.assertRaises(black.InvalidInput):
-            black.lib2to3_parse(py3_only, {TargetVersion.PY27})
         black.lib2to3_parse(py3_only, {TargetVersion.PY36})
-        black.lib2to3_parse(py3_only, {TargetVersion.PY27, 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("decorators")
+        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)
@@ -791,7 +874,7 @@ class BlackTestCase(BlackBaseTestCase):
         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("function")
+        source, expected = read_data("simple_cases", "function")
         node = black.lib2to3_parse(source)
         expected_features = {
             Feature.TRAILING_COMMA_IN_CALL,
@@ -801,7 +884,7 @@ class BlackTestCase(BlackBaseTestCase):
         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("expression")
+        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)
@@ -810,6 +893,56 @@ class BlackTestCase(BlackBaseTestCase):
         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_get_future_imports(self) -> None:
         node = black.lib2to3_parse("\n")
@@ -841,9 +974,10 @@ class BlackTestCase(BlackBaseTestCase):
         )
         self.assertEqual({"unicode_literals", "print"}, black.get_future_imports(node))
 
+    @pytest.mark.incompatible_with_mypyc
     def test_debug_visitor(self) -> None:
-        source, _ = read_data("debug_visitor.py")
-        expected, _ = read_data("debug_visitor.out")
+        source, _ = read_data("miscellaneous", "debug_visitor")
+        expected, _ = read_data("miscellaneous", "debug_visitor.out")
         out_lines = []
         err_lines = []
 
@@ -866,8 +1000,8 @@ class BlackTestCase(BlackBaseTestCase):
         )
 
     def test_format_file_contents(self) -> None:
-        empty = ""
         mode = DEFAULT_MODE
+        empty = ""
         with self.assertRaises(black.NothingChanged):
             black.format_file_contents(empty, mode=mode, fast=False)
         just_nl = "\n"
@@ -885,12 +1019,24 @@ class BlackTestCase(BlackBaseTestCase):
             black.format_file_contents(invalid, mode=mode, fast=False)
         self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
 
+        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)
+
     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)
 
+    @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 = []
@@ -907,12 +1053,12 @@ class BlackTestCase(BlackBaseTestCase):
                 self.assertFormatEqual("j = [1, 2, 3]", "j = [1, 2, 3,]")
 
         out_str = "".join(out_lines)
-        self.assertTrue("Expected tree:" in out_str)
-        self.assertTrue("Actual tree:" in out_str)
+        self.assertIn("Expected tree:", out_str)
+        self.assertIn("Actual tree:", out_str)
         self.assertEqual("".join(err_lines), "")
 
     @event_loop()
-    @patch("black.ProcessPoolExecutor", MagicMock(side_effect=OSError))
+    @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 [
@@ -926,31 +1072,34 @@ class BlackTestCase(BlackBaseTestCase):
     def test_check_diff_use_together(self) -> None:
         with cache_dir():
             # Files which will be reformatted.
-            src1 = (THIS_DIR / "data" / "string_quotes.py").resolve()
+            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 / "data" / "composition.py").resolve()
+            src2 = get_case_path("simple_cases", "composition")
             self.invokeBlack([str(src2), "--diff", "--check"])
             # Multi file command.
             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():
+            self.invokeBlack([], exit_code=1)
+
+    def test_src_and_code_fails(self) -> None:
         with cache_dir():
-            # Without an argument, black exits with error code 0.
-            self.invokeBlack([])
+            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}")
             self.invokeBlack([str(workspace.resolve())])
 
     def test_single_file_force_pyi(self) -> None:
         pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
-        contents, expected = read_data("force_pyi")
+        contents, expected = read_data("miscellaneous", "force_pyi")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
             with open(path, "w") as fh:
@@ -971,7 +1120,7 @@ class BlackTestCase(BlackBaseTestCase):
     def test_multi_file_force_pyi(self) -> None:
         reg_mode = DEFAULT_MODE
         pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
-        contents, expected = read_data("force_pyi")
+        contents, expected = read_data("miscellaneous", "force_pyi")
         with cache_dir() as workspace:
             paths = [
                 (workspace / "file1.py").resolve(),
@@ -993,7 +1142,7 @@ class BlackTestCase(BlackBaseTestCase):
                 self.assertNotIn(str(path), normal_cache)
 
     def test_pipe_force_pyi(self) -> None:
-        source, expected = read_data("force_pyi")
+        source, expected = read_data("miscellaneous", "force_pyi")
         result = CliRunner().invoke(
             black.main, ["-", "-q", "--pyi"], input=BytesIO(source.encode("utf8"))
         )
@@ -1004,7 +1153,7 @@ class BlackTestCase(BlackBaseTestCase):
     def test_single_file_force_py36(self) -> None:
         reg_mode = DEFAULT_MODE
         py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
-        source, expected = read_data("force_py36")
+        source, expected = read_data("miscellaneous", "force_py36")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
             with open(path, "w") as fh:
@@ -1023,7 +1172,7 @@ class BlackTestCase(BlackBaseTestCase):
     def test_multi_file_force_py36(self) -> None:
         reg_mode = DEFAULT_MODE
         py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
-        source, expected = read_data("force_py36")
+        source, expected = read_data("miscellaneous", "force_py36")
         with cache_dir() as workspace:
             paths = [
                 (workspace / "file1.py").resolve(),
@@ -1045,7 +1194,7 @@ class BlackTestCase(BlackBaseTestCase):
                 self.assertNotIn(str(path), normal_cache)
 
     def test_pipe_force_py36(self) -> None:
-        source, expected = read_data("force_py36")
+        source, expected = read_data("miscellaneous", "force_py36")
         result = CliRunner().invoke(
             black.main,
             ["-", "-q", "--target-version=py36"],
@@ -1055,6 +1204,7 @@ class BlackTestCase(BlackBaseTestCase):
         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",
@@ -1072,6 +1222,7 @@ class BlackTestCase(BlackBaseTestCase):
             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",
@@ -1094,6 +1245,7 @@ class BlackTestCase(BlackBaseTestCase):
             # __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",
@@ -1118,6 +1270,7 @@ class BlackTestCase(BlackBaseTestCase):
             # __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",
@@ -1142,6 +1295,7 @@ class BlackTestCase(BlackBaseTestCase):
             # __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",
@@ -1150,7 +1304,7 @@ class BlackTestCase(BlackBaseTestCase):
             report = MagicMock()
             # Even with an existing file, since we are forcing stdin, black
             # should output to stdout and not modify the file inplace
-            p = Path(str(THIS_DIR / "data/collections.py"))
+            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}")
@@ -1167,8 +1321,51 @@ class BlackTestCase(BlackBaseTestCase):
             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()
-        with patch("io.TextIOWrapper", lambda *args, **kwargs: output):
+        io_TextIOWrapper = io.TextIOWrapper
+        with patch("io.TextIOWrapper", _new_wrapper(output, io_TextIOWrapper)):
             try:
                 black.format_stdin_to_stdout(
                     fast=True,
@@ -1186,13 +1383,32 @@ class BlackTestCase(BlackBaseTestCase):
 
     def test_required_version_matches_version(self) -> None:
         self.invokeBlack(
-            ["--required-version", black.__version__], exit_code=0, ignore_config=True
+            ["--required-version", black.__version__, "-c", "0"],
+            exit_code=0,
+            ignore_config=True,
         )
 
-    def test_required_version_does_not_match_version(self) -> None:
+    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", "20.99b"], exit_code=1, ignore_config=True
+            ["--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:
@@ -1219,29 +1435,42 @@ class BlackTestCase(BlackBaseTestCase):
             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_shhh_click(self) -> None:
         try:
-            from click import _unicodefun
-        except ModuleNotFoundError:
+            from click import _unicodefun  # type: ignore
+        except ImportError:
             self.skipTest("Incompatible Click version")
-        if not hasattr(_unicodefun, "_verify_python3_env"):
+
+        if not hasattr(_unicodefun, "_verify_python_env"):
             self.skipTest("Incompatible Click version")
+
         # First, let's see if Click is crashing with a preferred ASCII charset.
         with patch("locale.getpreferredencoding") as gpe:
             gpe.return_value = "ASCII"
             with self.assertRaises(RuntimeError):
-                _unicodefun._verify_python3_env()  # type: ignore
+                _unicodefun._verify_python_env()
         # Now, let's silence Click...
         black.patch_click()
         # ...and confirm it's silent.
         with patch("locale.getpreferredencoding") as gpe:
             gpe.return_value = "ASCII"
             try:
-                _unicodefun._verify_python3_env()  # type: ignore
+                _unicodefun._verify_python_env()
             except RuntimeError as re:
                 self.fail(f"`patch_click()` failed, exception still raised: {re}")
 
@@ -1279,6 +1508,7 @@ class BlackTestCase(BlackBaseTestCase):
         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?$")
         self.assertEqual(config["include"], r"\.py?$")
 
@@ -1296,6 +1526,7 @@ class BlackTestCase(BlackBaseTestCase):
         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)
@@ -1313,10 +1544,38 @@ class BlackTestCase(BlackBaseTestCase):
             src_python.touch()
 
             self.assertEqual(
-                black.find_project_root((src_dir, test_dir)), root.resolve()
+                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"),
             )
-            self.assertEqual(black.find_project_root((src_dir,)), src_dir.resolve())
-            self.assertEqual(black.find_project_root((src_python,)), src_dir.resolve())
+
+            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",
@@ -1363,19 +1622,37 @@ class BlackTestCase(BlackBaseTestCase):
             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("missing_final_newline.py")
+        source, _ = read_data("miscellaneous", "missing_final_newline")
         # read_data adds a trailing newline
         source = source.rstrip()
-        expected, _ = read_data("missing_final_newline.diff")
+        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 "
@@ -1390,27 +1667,6 @@ class BlackTestCase(BlackBaseTestCase):
         actual = diff_header.sub(DETERMINISTIC_HEADER, actual)
         self.assertEqual(actual, expected)
 
-    @pytest.mark.python2
-    def test_docstring_reformat_for_py27(self) -> None:
-        """
-        Check that stripping trailing whitespace from Python 2 docstrings
-        doesn't trigger a "not equivalent to source" error
-        """
-        source = (
-            b'def foo():\r\n    """Testing\r\n    Testing """\r\n    print "Foo"\r\n'
-        )
-        expected = 'def foo():\n    """Testing\n    Testing"""\n    print "Foo"\n'
-
-        result = CliRunner().invoke(
-            black.main,
-            ["-", "-q", "--target-version=py27"],
-            input=BytesIO(source),
-        )
-
-        self.assertEqual(result.exit_code, 0)
-        actual = result.output
-        self.assertFormatEqual(actual, expected)
-
     @staticmethod
     def compare_results(
         result: click.testing.Result, expected_value: str, expected_exit_code: int
@@ -1483,6 +1739,7 @@ class BlackTestCase(BlackBaseTestCase):
         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
@@ -1507,6 +1764,7 @@ class BlackTestCase(BlackBaseTestCase):
 
             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.
@@ -1527,6 +1785,7 @@ class BlackTestCase(BlackBaseTestCase):
                 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.
@@ -1546,8 +1805,54 @@ class BlackTestCase(BlackBaseTestCase):
                     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:
@@ -1573,7 +1878,7 @@ class TestCaching:
     def test_cache_multiple_files(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir() as workspace, patch(
-            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
+            "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
             one = (workspace / "one.py").resolve()
             with one.open("w") as fobj:
@@ -1618,7 +1923,9 @@ class TestCaching:
                 src = (workspace / f"test{tag}.py").resolve()
                 with src.open("w") as fobj:
                     fobj.write("print('hello')")
-            with patch("black.Manager", wraps=multiprocessing.Manager) as mgr:
+            with patch(
+                "black.concurrency.Manager", wraps=multiprocessing.Manager
+            ) as mgr:
                 cmd = ["--diff", str(workspace)]
                 if color:
                     cmd.append("--color")
@@ -1665,7 +1972,7 @@ class TestCaching:
                 str(cached): black.get_cache_info(cached),
                 str(cached_but_changed): (0.0, 0),
             }
-            todo, done = black.filter_cached(
+            todo, done = black.cache.filter_cached(
                 cache, {uncached, cached, cached_but_changed}
             )
             assert todo == {uncached, cached_but_changed}
@@ -1682,7 +1989,7 @@ class TestCaching:
     def test_failed_formatting_does_not_get_cached(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir() as workspace, patch(
-            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
+            "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
             failing = (workspace / "failing.py").resolve()
             with failing.open("w") as fobj:
@@ -1718,6 +2025,7 @@ 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,
@@ -1733,7 +2041,7 @@ def assert_collected_sources(
     )
     gs_force_exclude = None if force_exclude is None else compile_pattern(force_exclude)
     collected = black.get_sources(
-        ctx=FakeContext(),
+        ctx=ctx or FakeContext(),
         src=gs_src,
         quiet=False,
         verbose=False,
@@ -1744,7 +2052,7 @@ def assert_collected_sources(
         report=black.Report(),
         stdin_filename=stdin_filename,
     )
-    assert sorted(list(collected)) == sorted(gs_expected)
+    assert sorted(collected) == sorted(gs_expected)
 
 
 class TestFileCollection:
@@ -1769,9 +2077,22 @@ class TestFileCollection:
             base / "b/.definitely_exclude/a.pyi",
         ]
         src = [base / "b/"]
-        assert_collected_sources(src, expected, extend_exclude=r"/exclude/")
+        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())
+    @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.
@@ -1804,7 +2125,7 @@ class TestFileCollection:
                 None,
                 None,
                 report,
-                gitignore,
+                {path: gitignore},
                 verbose=False,
                 quiet=False,
             )
@@ -1833,13 +2154,20 @@ class TestFileCollection:
                 None,
                 None,
                 report,
-                root_gitignore,
+                {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"
@@ -1864,6 +2192,32 @@ class TestFileCollection:
         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 = DATA_DIR / "include_exclude_tests"
         src = [path]
@@ -1894,6 +2248,7 @@ class TestFileCollection:
             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()
@@ -1907,7 +2262,6 @@ class TestFileCollection:
         path.iterdir.return_value = [child]
         child.resolve.return_value = Path("/a/b/c")
         child.as_posix.return_value = "/a/b/c"
-        child.is_symlink.return_value = True
         try:
             list(
                 black.gen_python_files(
@@ -1918,7 +2272,7 @@ class TestFileCollection:
                     None,
                     None,
                     report,
-                    gitignore,
+                    {path: gitignore},
                     verbose=False,
                     quiet=False,
                 )
@@ -1927,39 +2281,14 @@ class TestFileCollection:
             pytest.fail(f"`get_python_files_in_dir()` failed: {ve}")
         path.iterdir.assert_called_once()
         child.resolve.assert_called_once()
-        child.is_symlink.assert_called_once()
-        # `child` should behave like a strange file which resolved path is clearly
-        # outside of the `root` directory.
-        child.is_symlink.return_value = False
-        with pytest.raises(ValueError):
-            list(
-                black.gen_python_files(
-                    path.iterdir(),
-                    root,
-                    include,
-                    exclude,
-                    None,
-                    None,
-                    report,
-                    gitignore,
-                    verbose=False,
-                    quiet=False,
-                )
-            )
-        path.iterdir.assert_called()
-        assert path.iterdir.call_count == 2
-        child.resolve.assert_called()
-        assert child.resolve.call_count == 2
-        child.is_symlink.assert_called()
-        assert child.is_symlink.call_count == 2
-
-    @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
+
+    @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())
+    @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")
@@ -1971,7 +2300,7 @@ class TestFileCollection:
             stdin_filename=stdin_filename,
         )
 
-    @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
+    @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
@@ -1987,7 +2316,7 @@ class TestFileCollection:
             stdin_filename=stdin_filename,
         )
 
-    @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
+    @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
@@ -2003,7 +2332,7 @@ class TestFileCollection:
             stdin_filename=stdin_filename,
         )
 
-    @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
+    @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
@@ -2017,8 +2346,12 @@ class TestFileCollection:
         )
 
 
-with open(black.__file__, "r", encoding="utf-8") as _bf:
-    black_source_lines = _bf.readlines()
+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(