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Update PyCharm integrations instructions to avoid running on external changes (#1769)
[etc/vim.git] / tests / test_black.py
index 1b282b8d41134f8d6feda6867e67f2a7b1ebdff9..e17f43b88d439b7988003dea63b9cd07112d0046 100644 (file)
@@ -1,19 +1,35 @@
 #!/usr/bin/env python3
+import multiprocessing
 import asyncio
 import logging
 from concurrent.futures import ThreadPoolExecutor
 from contextlib import contextmanager
+from dataclasses import replace
 from functools import partial
+import inspect
 from io import BytesIO, TextIOWrapper
 import os
 from pathlib import Path
+from platform import system
 import regex as re
 import sys
 from tempfile import TemporaryDirectory
-from typing import Any, BinaryIO, Generator, List, Tuple, Iterator, TypeVar
+import types
+from typing import (
+    Any,
+    BinaryIO,
+    Callable,
+    Dict,
+    Generator,
+    List,
+    Tuple,
+    Iterator,
+    TypeVar,
+)
 import unittest
 from unittest.mock import patch, MagicMock
 
+import click
 from click import unstyle
 from click.testing import CliRunner
 
@@ -35,16 +51,21 @@ from pathspec import PathSpec
 from .test_primer import PrimerCLITests  # noqa: F401
 
 
-ff = partial(black.format_file_in_place, mode=black.FileMode(), fast=True)
-fs = partial(black.format_str, mode=black.FileMode())
+DEFAULT_MODE = black.FileMode(experimental_string_processing=True)
+ff = partial(black.format_file_in_place, mode=DEFAULT_MODE, fast=True)
+fs = partial(black.format_str, mode=DEFAULT_MODE)
 THIS_FILE = Path(__file__)
 THIS_DIR = THIS_FILE.parent
 PROJECT_ROOT = THIS_DIR.parent
 DETERMINISTIC_HEADER = "[Deterministic header]"
 EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
-PY36_ARGS = [
-    f"--target-version={version.name.lower()}" for version in black.PY36_VERSIONS
-]
+PY36_VERSIONS = {
+    TargetVersion.PY36,
+    TargetVersion.PY37,
+    TargetVersion.PY38,
+    TargetVersion.PY39,
+}
+PY36_ARGS = [f"--target-version={version.name.lower()}" for version in PY36_VERSIONS]
 T = TypeVar("T")
 R = TypeVar("R")
 
@@ -109,6 +130,20 @@ def skip_if_exception(e: str) -> Iterator[None]:
             raise
 
 
+class FakeContext(click.Context):
+    """A fake click Context for when calling functions that need it."""
+
+    def __init__(self) -> None:
+        self.default_map: Dict[str, Any] = {}
+
+
+class FakeParameter(click.Parameter):
+    """A fake click Parameter for when calling functions that need it."""
+
+    def __init__(self) -> None:
+        pass
+
+
 class BlackRunner(CliRunner):
     """Modify CliRunner so that stderr is not merged with stdout.
 
@@ -136,6 +171,7 @@ class BlackRunner(CliRunner):
 
 class BlackTestCase(unittest.TestCase):
     maxDiff = None
+    _diffThreshold = 2 ** 20
 
     def assertFormatEqual(self, expected: str, actual: str) -> None:
         if actual != expected and not os.environ.get("SKIP_AST_PRINT"):
@@ -154,7 +190,7 @@ class BlackTestCase(unittest.TestCase):
                 list(bdv.visit(exp_node))
             except Exception as ve:
                 black.err(str(ve))
-        self.assertEqual(expected, actual)
+        self.assertMultiLineEqual(expected, actual)
 
     def invokeBlack(
         self, args: List[str], exit_code: int = 0, ignore_config: bool = True
@@ -175,13 +211,13 @@ class BlackTestCase(unittest.TestCase):
         )
 
     @patch("black.dump_to_file", dump_to_stderr)
-    def checkSourceFile(self, name: str) -> None:
+    def checkSourceFile(self, name: str, mode: black.FileMode = DEFAULT_MODE) -> None:
         path = THIS_DIR.parent / name
         source, expected = read_data(str(path), data=False)
-        actual = fs(source)
+        actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, mode)
         self.assertFalse(ff(path))
 
     @patch("black.dump_to_file", dump_to_stderr)
@@ -190,7 +226,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_empty_ff(self) -> None:
         expected = ""
@@ -252,7 +288,7 @@ class BlackTestCase(unittest.TestCase):
         self.assertEqual(result.exit_code, 0)
         self.assertFormatEqual(expected, result.output)
         black.assert_equivalent(source, result.output)
-        black.assert_stable(source, result.output, black.FileMode())
+        black.assert_stable(source, result.output, DEFAULT_MODE)
 
     def test_piping_diff(self) -> None:
         diff_header = re.compile(
@@ -305,7 +341,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_function2(self) -> None:
@@ -313,6 +349,21 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def _test_wip(self) -> None:
+        source, expected = read_data("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, black.FileMode())
 
     @patch("black.dump_to_file", dump_to_stderr)
@@ -321,7 +372,28 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @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_expression(self) -> None:
@@ -329,14 +401,14 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_pep_572(self) -> None:
         source, expected = read_data("pep_572")
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
         if sys.version_info >= (3, 8):
             black.assert_equivalent(source, actual)
 
@@ -360,7 +432,7 @@ class BlackTestCase(unittest.TestCase):
         self.assertFormatEqual(expected, actual)
         with patch("black.dump_to_file", dump_to_stderr):
             black.assert_equivalent(source, actual)
-            black.assert_stable(source, actual, black.FileMode())
+            black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_expression_diff(self) -> None:
         source, _ = read_data("expression.py")
@@ -412,14 +484,14 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_pep_570(self) -> None:
         source, expected = read_data("pep_570")
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
         if sys.version_info >= (3, 8):
             black.assert_equivalent(source, actual)
 
@@ -437,8 +509,8 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
-        mode = black.FileMode(string_normalization=False)
+        black.assert_stable(source, actual, DEFAULT_MODE)
+        mode = replace(DEFAULT_MODE, string_normalization=False)
         not_normalized = fs(source, mode=mode)
         self.assertFormatEqual(source.replace("\\\n", ""), not_normalized)
         black.assert_equivalent(source, not_normalized)
@@ -450,7 +522,17 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_docstring_no_string_normalization(self) -> None:
+        """Like test_docstring but with string normalization off."""
+        source, expected = read_data("docstring_no_string_normalization")
+        mode = replace(DEFAULT_MODE, string_normalization=False)
+        actual = fs(source, mode=mode)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, mode)
 
     def test_long_strings(self) -> None:
         """Tests for splitting long strings."""
@@ -458,7 +540,15 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    def test_long_strings_flag_disabled(self) -> None:
+        """Tests for turning off the string processing logic."""
+        source, expected = read_data("long_strings_flag_disabled")
+        mode = replace(DEFAULT_MODE, experimental_string_processing=False)
+        actual = fs(source, mode=mode)
+        self.assertFormatEqual(expected, actual)
+        black.assert_stable(expected, actual, mode)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_long_strings__edge_case(self) -> None:
@@ -467,7 +557,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_long_strings__regression(self) -> None:
@@ -476,7 +566,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_slices(self) -> None:
@@ -484,7 +574,15 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_percent_precedence(self) -> None:
+        source, expected = read_data("percent_precedence")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments(self) -> None:
@@ -492,7 +590,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments2(self) -> None:
@@ -500,7 +598,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments3(self) -> None:
@@ -508,7 +606,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments4(self) -> None:
@@ -516,7 +614,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments5(self) -> None:
@@ -524,7 +622,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments6(self) -> None:
@@ -532,15 +630,16 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments7(self) -> None:
         source, expected = read_data("comments7")
-        actual = fs(source)
+        mode = replace(DEFAULT_MODE, target_versions={black.TargetVersion.PY38})
+        actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comment_after_escaped_newline(self) -> None:
@@ -548,7 +647,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_cantfit(self) -> None:
@@ -556,7 +655,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_import_spacing(self) -> None:
@@ -564,7 +663,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_composition(self) -> None:
@@ -572,7 +671,16 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_composition_no_trailing_comma(self) -> None:
+        source, expected = read_data("composition_no_trailing_comma")
+        mode = replace(DEFAULT_MODE, target_versions={black.TargetVersion.PY38})
+        actual = fs(source, mode=mode)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_empty_lines(self) -> None:
@@ -580,7 +688,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_remove_parens(self) -> None:
@@ -588,7 +696,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_string_prefixes(self) -> None:
@@ -596,12 +704,12 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_numeric_literals(self) -> None:
         source, expected = read_data("numeric_literals")
-        mode = black.FileMode(target_versions=black.PY36_VERSIONS)
+        mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
         actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
@@ -610,7 +718,7 @@ class BlackTestCase(unittest.TestCase):
     @patch("black.dump_to_file", dump_to_stderr)
     def test_numeric_literals_ignoring_underscores(self) -> None:
         source, expected = read_data("numeric_literals_skip_underscores")
-        mode = black.FileMode(target_versions=black.PY36_VERSIONS)
+        mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
         actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
@@ -621,7 +729,7 @@ class BlackTestCase(unittest.TestCase):
         source, expected = read_data("numeric_literals_py2")
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_python2(self) -> None:
@@ -629,12 +737,12 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_python2_print_function(self) -> None:
         source, expected = read_data("python2_print_function")
-        mode = black.FileMode(target_versions={TargetVersion.PY27})
+        mode = replace(DEFAULT_MODE, target_versions={TargetVersion.PY27})
         actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
@@ -646,11 +754,11 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_stub(self) -> None:
-        mode = black.FileMode(is_pyi=True)
+        mode = replace(DEFAULT_MODE, is_pyi=True)
         source, expected = read_data("stub.pyi")
         actual = fs(source, mode=mode)
         self.assertFormatEqual(expected, actual)
@@ -665,7 +773,7 @@ class BlackTestCase(unittest.TestCase):
         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, black.FileMode())
+        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
@@ -680,7 +788,7 @@ class BlackTestCase(unittest.TestCase):
         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, black.FileMode())
+        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
@@ -694,7 +802,17 @@ class BlackTestCase(unittest.TestCase):
         major, minor = sys.version_info[:2]
         if major > 3 or (major == 3 and minor >= 8):
             black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_python39(self) -> None:
+        source, expected = read_data("python39")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        major, minor = sys.version_info[:2]
+        if major > 3 or (major == 3 and minor >= 9):
+            black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff(self) -> None:
@@ -702,7 +820,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff2(self) -> None:
@@ -710,7 +828,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff3(self) -> None:
@@ -718,7 +836,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff4(self) -> None:
@@ -726,7 +844,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_remove_empty_parentheses_after_class(self) -> None:
@@ -734,7 +852,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_new_line_between_class_and_code(self) -> None:
@@ -742,7 +860,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_bracket_match(self) -> None:
@@ -750,7 +868,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_tuple_assign(self) -> None:
@@ -758,7 +876,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_beginning_backslash(self) -> None:
@@ -766,7 +884,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_tab_comment_indentation(self) -> None:
         contents_tab = "if 1:\n\tif 2:\n\t\tpass\n\t# comment\n\tpass\n"
@@ -1108,6 +1226,39 @@ class BlackTestCase(unittest.TestCase):
         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")
+        # 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_get_features_used(self) -> None:
         node = black.lib2to3_parse("def f(*, arg): ...\n")
         self.assertEqual(black.get_features_used(node), set())
@@ -1195,7 +1346,7 @@ class BlackTestCase(unittest.TestCase):
 
     def test_format_file_contents(self) -> None:
         empty = ""
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with self.assertRaises(black.NothingChanged):
             black.format_file_contents(empty, mode=mode, fast=False)
         just_nl = "\n"
@@ -1240,7 +1391,7 @@ class BlackTestCase(unittest.TestCase):
         self.assertEqual("".join(err_lines), "")
 
     def test_cache_broken_file(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace:
             cache_file = black.get_cache_file(mode)
             with cache_file.open("w") as fobj:
@@ -1254,7 +1405,7 @@ class BlackTestCase(unittest.TestCase):
             self.assertIn(src, cache)
 
     def test_cache_single_file_already_cached(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
@@ -1266,7 +1417,7 @@ class BlackTestCase(unittest.TestCase):
 
     @event_loop()
     def test_cache_multiple_files(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace, patch(
             "black.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
@@ -1287,17 +1438,63 @@ class BlackTestCase(unittest.TestCase):
             self.assertIn(two, cache)
 
     def test_no_cache_when_writeback_diff(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
-            self.invokeBlack([str(src), "--diff"])
-            cache_file = black.get_cache_file(mode)
-            self.assertFalse(cache_file.exists())
+            with patch("black.read_cache") as read_cache, patch(
+                "black.write_cache"
+            ) as write_cache:
+                self.invokeBlack([str(src), "--diff"])
+                cache_file = black.get_cache_file(mode)
+                self.assertFalse(cache_file.exists())
+                write_cache.assert_not_called()
+                read_cache.assert_not_called()
+
+    def test_no_cache_when_writeback_color_diff(self) -> None:
+        mode = DEFAULT_MODE
+        with cache_dir() as workspace:
+            src = (workspace / "test.py").resolve()
+            with src.open("w") as fobj:
+                fobj.write("print('hello')")
+            with patch("black.read_cache") as read_cache, patch(
+                "black.write_cache"
+            ) as write_cache:
+                self.invokeBlack([str(src), "--diff", "--color"])
+                cache_file = black.get_cache_file(mode)
+                self.assertFalse(cache_file.exists())
+                write_cache.assert_not_called()
+                read_cache.assert_not_called()
+
+    @event_loop()
+    def test_output_locking_when_writeback_diff(self) -> None:
+        with cache_dir() as workspace:
+            for tag in range(0, 4):
+                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:
+                self.invokeBlack(["--diff", str(workspace)], 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()
+
+    @event_loop()
+    def test_output_locking_when_writeback_color_diff(self) -> None:
+        with cache_dir() as workspace:
+            for tag in range(0, 4):
+                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:
+                self.invokeBlack(["--diff", "--color", str(workspace)], 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 = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir():
             result = CliRunner().invoke(
                 black.main, ["-"], input=BytesIO(b"print('hello')")
@@ -1307,12 +1504,12 @@ class BlackTestCase(unittest.TestCase):
             self.assertFalse(cache_file.exists())
 
     def test_read_cache_no_cachefile(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir():
             self.assertEqual(black.read_cache(mode), {})
 
     def test_write_cache_read_cache(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             src.touch()
@@ -1338,7 +1535,7 @@ class BlackTestCase(unittest.TestCase):
             self.assertEqual(done, {cached})
 
     def test_write_cache_creates_directory_if_needed(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir(exists=False) as workspace:
             self.assertFalse(workspace.exists())
             black.write_cache({}, [], mode)
@@ -1346,7 +1543,7 @@ class BlackTestCase(unittest.TestCase):
 
     @event_loop()
     def test_failed_formatting_does_not_get_cached(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir() as workspace, patch(
             "black.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
@@ -1362,7 +1559,7 @@ class BlackTestCase(unittest.TestCase):
             self.assertIn(clean, cache)
 
     def test_write_cache_write_fail(self) -> None:
-        mode = black.FileMode()
+        mode = DEFAULT_MODE
         with cache_dir(), patch.object(Path, "open") as mock:
             mock.side_effect = OSError
             black.write_cache({}, [], mode)
@@ -1405,8 +1602,8 @@ class BlackTestCase(unittest.TestCase):
             self.invokeBlack([str(workspace.resolve())])
 
     def test_read_cache_line_lengths(self) -> None:
-        mode = black.FileMode()
-        short_mode = black.FileMode(line_length=1)
+        mode = DEFAULT_MODE
+        short_mode = replace(DEFAULT_MODE, line_length=1)
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
             path.touch()
@@ -1421,11 +1618,10 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_single_file_force_pyi(self) -> None:
-        reg_mode = black.FileMode()
-        pyi_mode = black.FileMode(is_pyi=True)
+        pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
         contents, expected = read_data("force_pyi")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
@@ -1437,14 +1633,16 @@ class BlackTestCase(unittest.TestCase):
             # verify cache with --pyi is separate
             pyi_cache = black.read_cache(pyi_mode)
             self.assertIn(path, pyi_cache)
-            normal_cache = black.read_cache(reg_mode)
+            normal_cache = black.read_cache(DEFAULT_MODE)
             self.assertNotIn(path, normal_cache)
-        self.assertEqual(actual, expected)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(contents, actual)
+        black.assert_stable(contents, actual, pyi_mode)
 
     @event_loop()
     def test_multi_file_force_pyi(self) -> None:
-        reg_mode = black.FileMode()
-        pyi_mode = black.FileMode(is_pyi=True)
+        reg_mode = DEFAULT_MODE
+        pyi_mode = replace(DEFAULT_MODE, is_pyi=True)
         contents, expected = read_data("force_pyi")
         with cache_dir() as workspace:
             paths = [
@@ -1476,8 +1674,8 @@ class BlackTestCase(unittest.TestCase):
         self.assertFormatEqual(actual, expected)
 
     def test_single_file_force_py36(self) -> None:
-        reg_mode = black.FileMode()
-        py36_mode = black.FileMode(target_versions=black.PY36_VERSIONS)
+        reg_mode = DEFAULT_MODE
+        py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
         source, expected = read_data("force_py36")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
@@ -1495,8 +1693,8 @@ class BlackTestCase(unittest.TestCase):
 
     @event_loop()
     def test_multi_file_force_py36(self) -> None:
-        reg_mode = black.FileMode()
-        py36_mode = black.FileMode(target_versions=black.PY36_VERSIONS)
+        reg_mode = DEFAULT_MODE
+        py36_mode = replace(DEFAULT_MODE, target_versions=PY36_VERSIONS)
         source, expected = read_data("force_py36")
         with cache_dir() as workspace:
             paths = [
@@ -1523,7 +1721,7 @@ class BlackTestCase(unittest.TestCase):
         actual = fs(source)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, black.FileMode())
+        black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_pipe_force_py36(self) -> None:
         source, expected = read_data("force_py36")
@@ -1550,7 +1748,32 @@ class BlackTestCase(unittest.TestCase):
         this_abs = THIS_DIR.resolve()
         sources.extend(
             black.gen_python_files(
-                path.iterdir(), this_abs, include, [exclude], report, gitignore
+                path.iterdir(), this_abs, include, exclude, None, report, gitignore
+            )
+        )
+        self.assertEqual(sorted(expected), sorted(sources))
+
+    @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
+    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 = THIS_DIR / "data" / "include_exclude_tests"
+        include = ""
+        exclude = r"/exclude/|a\.py"
+        src = str(path / "b/exclude/a.py")
+        report = black.Report()
+        expected = [Path(path / "b/exclude/a.py")]
+        sources = list(
+            black.get_sources(
+                ctx=FakeContext(),
+                src=(src,),
+                quiet=True,
+                verbose=False,
+                include=include,
+                exclude=exclude,
+                force_exclude=None,
+                report=report,
             )
         )
         self.assertEqual(sorted(expected), sorted(sources))
@@ -1571,7 +1794,7 @@ class BlackTestCase(unittest.TestCase):
         this_abs = THIS_DIR.resolve()
         sources.extend(
             black.gen_python_files(
-                path.iterdir(), this_abs, include, [exclude], report, gitignore
+                path.iterdir(), this_abs, include, exclude, None, report, gitignore
             )
         )
         self.assertEqual(sorted(expected), sorted(sources))
@@ -1599,7 +1822,8 @@ class BlackTestCase(unittest.TestCase):
                 path.iterdir(),
                 this_abs,
                 empty,
-                [re.compile(black.DEFAULT_EXCLUDES)],
+                re.compile(black.DEFAULT_EXCLUDES),
+                None,
                 report,
                 gitignore,
             )
@@ -1626,7 +1850,8 @@ class BlackTestCase(unittest.TestCase):
                 path.iterdir(),
                 this_abs,
                 re.compile(black.DEFAULT_INCLUDES),
-                [empty],
+                empty,
+                None,
                 report,
                 gitignore,
             )
@@ -1683,7 +1908,7 @@ class BlackTestCase(unittest.TestCase):
         try:
             list(
                 black.gen_python_files(
-                    path.iterdir(), root, include, exclude, report, gitignore
+                    path.iterdir(), root, include, exclude, None, report, gitignore
                 )
             )
         except ValueError as ve:
@@ -1697,7 +1922,7 @@ class BlackTestCase(unittest.TestCase):
         with self.assertRaises(ValueError):
             list(
                 black.gen_python_files(
-                    path.iterdir(), root, include, exclude, report, gitignore
+                    path.iterdir(), root, include, exclude, None, report, gitignore
                 )
             )
         path.iterdir.assert_called()
@@ -1762,6 +1987,71 @@ class BlackTestCase(unittest.TestCase):
         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["exclude"], r"\.pyi?$")
+        self.assertEqual(config["include"], r"\.py?$")
+
+    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_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()
+            )
+            self.assertEqual(black.find_project_root((src_dir,)), src_dir.resolve())
+            self.assertEqual(black.find_project_root((src_python,)), src_dir.resolve())
+
+    def test_bpo_33660_workaround(self) -> None:
+        if system() == "Windows":
+            return
+
+        # https://bugs.python.org/issue33660
+
+        old_cwd = Path.cwd()
+        try:
+            root = Path("/")
+            os.chdir(str(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")
+        finally:
+            os.chdir(str(old_cwd))
+
 
 class BlackDTestCase(AioHTTPTestCase):
     async def get_application(self) -> web.Application:
@@ -1931,5 +2221,31 @@ class BlackDTestCase(AioHTTPTestCase):
         self.assertIsNotNone(response.headers.get(blackd.BLACK_VERSION_HEADER))
 
 
+with open(black.__file__, "r", encoding="utf-8") as _bf:
+    black_source_lines = _bf.readlines()
+
+
+def tracefunc(frame: types.FrameType, event: str, arg: Any) -> Callable:
+    """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
+
+
 if __name__ == "__main__":
     unittest.main(module="test_black")