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

madduck's git repository

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

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

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

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

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

Update output display to job summary (#3914)
[etc/vim.git] / tests / test_black.py
index 9256698ea2792eb49ba559febe803afde73b9d60..c665eee3a6c20644e72a9728309c4c0f95e2b24d 100644 (file)
@@ -9,7 +9,6 @@ import os
 import re
 import sys
 import types
-import unittest
 from concurrent.futures import ThreadPoolExecutor
 from contextlib import contextmanager, redirect_stderr
 from dataclasses import replace
@@ -25,6 +24,7 @@ from typing import (
     List,
     Optional,
     Sequence,
+    Type,
     TypeVar,
     Union,
 )
@@ -40,7 +40,7 @@ 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_dir, get_cache_file
+from black.cache import FileData, get_cache_dir, get_cache_file
 from black.debug import DebugVisitor
 from black.output import color_diff, diff
 from black.report import Report
@@ -103,6 +103,7 @@ class FakeContext(click.Context):
 
     def __init__(self) -> None:
         self.default_map: Dict[str, Any] = {}
+        self.params: Dict[str, Any] = {}
         # Dummy root, since most of the tests don't care about it
         self.obj: Dict[str, Any] = {"root": PROJECT_ROOT}
 
@@ -147,12 +148,39 @@ class BlackTestCase(BlackBaseTestCase):
         tmp_file = Path(black.dump_to_file())
         try:
             self.assertFalse(ff(tmp_file, write_back=black.WriteBack.YES))
-            with open(tmp_file, encoding="utf8") as f:
-                actual = f.read()
+            actual = tmp_file.read_text(encoding="utf-8")
         finally:
             os.unlink(tmp_file)
         self.assertFormatEqual(expected, actual)
 
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_one_empty_line(self) -> None:
+        mode = black.Mode(preview=True)
+        for nl in ["\n", "\r\n"]:
+            source = expected = nl
+            assert_format(source, expected, mode=mode)
+
+    def test_one_empty_line_ff(self) -> None:
+        mode = black.Mode(preview=True)
+        for nl in ["\n", "\r\n"]:
+            expected = nl
+            tmp_file = Path(black.dump_to_file(nl))
+            if system() == "Windows":
+                # Writing files in text mode automatically uses the system newline,
+                # but in this case we don't want this for testing reasons. See:
+                # https://github.com/psf/black/pull/3348
+                with open(tmp_file, "wb") as f:
+                    f.write(nl.encode("utf-8"))
+            try:
+                self.assertFalse(
+                    ff(tmp_file, mode=mode, write_back=black.WriteBack.YES)
+                )
+                with open(tmp_file, "rb") as f:
+                    actual = f.read().decode("utf-8")
+            finally:
+                os.unlink(tmp_file)
+            self.assertFormatEqual(expected, actual)
+
     def test_experimental_string_processing_warns(self) -> None:
         self.assertWarns(
             black.mode.Deprecated, black.Mode, experimental_string_processing=True
@@ -168,7 +196,7 @@ class BlackTestCase(BlackBaseTestCase):
                 f"--line-length={black.DEFAULT_LINE_LENGTH}",
                 f"--config={EMPTY_CONFIG}",
             ],
-            input=BytesIO(source.encode("utf8")),
+            input=BytesIO(source.encode("utf-8")),
         )
         self.assertEqual(result.exit_code, 0)
         self.assertFormatEqual(expected, result.output)
@@ -178,8 +206,8 @@ class BlackTestCase(BlackBaseTestCase):
 
     def test_piping_diff(self) -> None:
         diff_header = re.compile(
-            r"(STDIN|STDOUT)\t\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d\.\d\d\d\d\d\d "
-            r"\+\d\d\d\d"
+            r"(STDIN|STDOUT)\t\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d\.\d\d\d\d\d\d"
+            r"\+\d\d:\d\d"
         )
         source, _ = read_data("simple_cases", "expression.py")
         expected, _ = read_data("simple_cases", "expression.diff")
@@ -191,7 +219,7 @@ class BlackTestCase(BlackBaseTestCase):
             f"--config={EMPTY_CONFIG}",
         ]
         result = BlackRunner().invoke(
-            black.main, args, input=BytesIO(source.encode("utf8"))
+            black.main, args, input=BytesIO(source.encode("utf-8"))
         )
         self.assertEqual(result.exit_code, 0)
         actual = diff_header.sub(DETERMINISTIC_HEADER, result.output)
@@ -209,7 +237,7 @@ class BlackTestCase(BlackBaseTestCase):
             f"--config={EMPTY_CONFIG}",
         ]
         result = BlackRunner().invoke(
-            black.main, args, input=BytesIO(source.encode("utf8"))
+            black.main, args, input=BytesIO(source.encode("utf-8"))
         )
         actual = result.output
         # Again, the contents are checked in a different test, so only look for colors.
@@ -242,13 +270,21 @@ class BlackTestCase(BlackBaseTestCase):
         versions = black.detect_target_versions(root)
         self.assertIn(black.TargetVersion.PY38, versions)
 
+    def test_pep_695_version_detection(self) -> None:
+        for file in ("type_aliases", "type_params"):
+            source, _ = read_data("py_312", file)
+            root = black.lib2to3_parse(source)
+            features = black.get_features_used(root)
+            self.assertIn(black.Feature.TYPE_PARAMS, features)
+            versions = black.detect_target_versions(root)
+            self.assertIn(black.TargetVersion.PY312, versions)
+
     def test_expression_ff(self) -> None:
         source, expected = read_data("simple_cases", "expression.py")
         tmp_file = Path(black.dump_to_file(source))
         try:
             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.YES))
-            with open(tmp_file, encoding="utf8") as f:
-                actual = f.read()
+            actual = tmp_file.read_text(encoding="utf-8")
         finally:
             os.unlink(tmp_file)
         self.assertFormatEqual(expected, actual)
@@ -262,7 +298,7 @@ class BlackTestCase(BlackBaseTestCase):
         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"
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
         )
         try:
             result = BlackRunner().invoke(
@@ -351,8 +387,7 @@ class BlackTestCase(BlackBaseTestCase):
             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()
+        actual = tmp_file.read_text(encoding="utf-8")
         self.assertFormatEqual(source, actual)
 
     def test_skip_source_first_line_when_mixing_newlines(self) -> None:
@@ -373,7 +408,7 @@ class BlackTestCase(BlackBaseTestCase):
         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"
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
         )
         try:
             result = BlackRunner().invoke(
@@ -390,7 +425,8 @@ class BlackTestCase(BlackBaseTestCase):
             msg = (
                 "Expected diff isn't equal to the actual. If you made changes to"
                 " expression.py and this is an anticipated difference, overwrite"
-                f" tests/data/expression_skip_magic_trailing_comma.diff with {dump}"
+                " tests/data/miscellaneous/expression_skip_magic_trailing_comma.diff"
+                f" with {dump}"
             )
             self.assertEqual(expected, actual, msg)
 
@@ -446,6 +482,51 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertFormatEqual(contents_spc, fs(contents_spc))
         self.assertFormatEqual(contents_spc, fs(contents_tab))
 
+    def test_false_positive_symlink_output_issue_3384(self) -> None:
+        # Emulate the behavior when using the CLI (`black ./child  --verbose`), which
+        # involves patching some `pathlib.Path` methods. In particular, `is_dir` is
+        # patched only on its first call: when checking if "./child" is a directory it
+        # should return True. The "./child" folder exists relative to the cwd when
+        # running from CLI, but fails when running the tests because cwd is different
+        project_root = Path(THIS_DIR / "data" / "nested_gitignore_tests")
+        working_directory = project_root / "root"
+        target_abspath = working_directory / "child"
+        target_contents = list(target_abspath.iterdir())
+
+        def mock_n_calls(responses: List[bool]) -> Callable[[], bool]:
+            def _mocked_calls() -> bool:
+                if responses:
+                    return responses.pop(0)
+                return False
+
+            return _mocked_calls
+
+        with patch("pathlib.Path.iterdir", return_value=target_contents), patch(
+            "pathlib.Path.cwd", return_value=working_directory
+        ), patch("pathlib.Path.is_dir", side_effect=mock_n_calls([True])):
+            # Note that the root folder (project_root) isn't the folder
+            # named "root" (aka working_directory)
+            report = MagicMock(verbose=True)
+            black.get_sources(
+                root=project_root,
+                src=("./child",),
+                quiet=False,
+                verbose=True,
+                include=DEFAULT_INCLUDE,
+                exclude=None,
+                report=report,
+                extend_exclude=None,
+                force_exclude=None,
+                stdin_filename=None,
+            )
+        assert not any(
+            mock_args[1].startswith("is a symbolic link that points outside")
+            for _, mock_args, _ in report.path_ignored.mock_calls
+        ), "A symbolic link was reported."
+        report.path_ignored.assert_called_once_with(
+            Path("root", "child", "b.py"), "matches a .gitignore file content"
+        )
+
     def test_report_verbose(self) -> None:
         report = Report(verbose=True)
         out_lines = []
@@ -490,10 +571,8 @@ 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)
@@ -502,10 +581,8 @@ 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")
@@ -514,10 +591,8 @@ 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")
@@ -526,10 +601,8 @@ 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)
@@ -538,28 +611,22 @@ 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:
@@ -601,10 +668,8 @@ 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)
@@ -612,10 +677,8 @@ 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")
@@ -624,10 +687,8 @@ 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")
@@ -635,10 +696,8 @@ 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)
@@ -646,28 +705,22 @@ 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:
@@ -711,10 +764,8 @@ 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)
@@ -723,10 +774,8 @@ 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")
@@ -735,10 +784,8 @@ 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")
@@ -746,10 +793,8 @@ 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)
@@ -757,28 +802,22 @@ 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:
@@ -971,8 +1010,8 @@ 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"
@@ -990,15 +1029,27 @@ 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)
 
+    @patch("tests.conftest.PRINT_FULL_TREE", True)
+    @patch("tests.conftest.PRINT_TREE_DIFF", False)
     @pytest.mark.incompatible_with_mypyc
-    @unittest.skipIf(os.environ.get("SKIP_AST_PRINT"), "user set SKIP_AST_PRINT")
-    def test_assertFormatEqual(self) -> None:
+    def test_assertFormatEqual_print_full_tree(self) -> None:
         out_lines = []
         err_lines = []
 
@@ -1017,6 +1068,29 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertIn("Actual tree:", out_str)
         self.assertEqual("".join(err_lines), "")
 
+    @patch("tests.conftest.PRINT_FULL_TREE", False)
+    @patch("tests.conftest.PRINT_TREE_DIFF", True)
+    @pytest.mark.incompatible_with_mypyc
+    def test_assertFormatEqual_print_tree_diff(self) -> None:
+        out_lines = []
+        err_lines = []
+
+        def out(msg: str, **kwargs: Any) -> None:
+            out_lines.append(msg)
+
+        def err(msg: str, **kwargs: Any) -> None:
+            err_lines.append(msg)
+
+        with patch("black.output._out", out), patch("black.output._err", err):
+            with self.assertRaises(AssertionError):
+                self.assertFormatEqual("j = [1, 2, 3]\n", "j = [1, 2, 3,]\n")
+
+        out_str = "".join(out_lines)
+        self.assertIn("Tree Diff:", out_str)
+        self.assertIn("+          COMMA", out_str)
+        self.assertIn("+ ','", out_str)
+        self.assertEqual("".join(err_lines), "")
+
     @event_loop()
     @patch("concurrent.futures.ProcessPoolExecutor", MagicMock(side_effect=OSError))
     def test_works_in_mono_process_only_environment(self) -> None:
@@ -1025,7 +1099,7 @@ class BlackTestCase(BlackBaseTestCase):
                 (workspace / "one.py").resolve(),
                 (workspace / "two.py").resolve(),
             ]:
-                f.write_text('print("hello")\n')
+                f.write_text('print("hello")\n', encoding="utf-8")
             self.invokeBlack([str(workspace)])
 
     @event_loop()
@@ -1062,16 +1136,14 @@ class BlackTestCase(BlackBaseTestCase):
         contents, expected = read_data("miscellaneous", "force_pyi")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
-            with open(path, "w") as fh:
-                fh.write(contents)
+            path.write_text(contents, encoding="utf-8")
             self.invokeBlack([str(path), "--pyi"])
-            with open(path, "r") as fh:
-                actual = fh.read()
+            actual = path.read_text(encoding="utf-8")
             # verify cache with --pyi is separate
-            pyi_cache = black.read_cache(pyi_mode)
-            self.assertIn(str(path), pyi_cache)
-            normal_cache = black.read_cache(DEFAULT_MODE)
-            self.assertNotIn(str(path), normal_cache)
+            pyi_cache = black.Cache.read(pyi_mode)
+            assert not pyi_cache.is_changed(path)
+            normal_cache = black.Cache.read(DEFAULT_MODE)
+            assert normal_cache.is_changed(path)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(contents, actual)
         black.assert_stable(contents, actual, pyi_mode)
@@ -1087,24 +1159,22 @@ class BlackTestCase(BlackBaseTestCase):
                 (workspace / "file2.py").resolve(),
             ]
             for path in paths:
-                with open(path, "w") as fh:
-                    fh.write(contents)
+                path.write_text(contents, encoding="utf-8")
             self.invokeBlack([str(p) for p in paths] + ["--pyi"])
             for path in paths:
-                with open(path, "r") as fh:
-                    actual = fh.read()
+                actual = path.read_text(encoding="utf-8")
                 self.assertEqual(actual, expected)
             # verify cache with --pyi is separate
-            pyi_cache = black.read_cache(pyi_mode)
-            normal_cache = black.read_cache(reg_mode)
+            pyi_cache = black.Cache.read(pyi_mode)
+            normal_cache = black.Cache.read(reg_mode)
             for path in paths:
-                self.assertIn(str(path), pyi_cache)
-                self.assertNotIn(str(path), normal_cache)
+                assert not pyi_cache.is_changed(path)
+                assert normal_cache.is_changed(path)
 
     def test_pipe_force_pyi(self) -> None:
         source, expected = read_data("miscellaneous", "force_pyi")
         result = CliRunner().invoke(
-            black.main, ["-", "-q", "--pyi"], input=BytesIO(source.encode("utf8"))
+            black.main, ["-", "-q", "--pyi"], input=BytesIO(source.encode("utf-8"))
         )
         self.assertEqual(result.exit_code, 0)
         actual = result.output
@@ -1116,16 +1186,14 @@ class BlackTestCase(BlackBaseTestCase):
         source, expected = read_data("miscellaneous", "force_py36")
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
-            with open(path, "w") as fh:
-                fh.write(source)
+            path.write_text(source, encoding="utf-8")
             self.invokeBlack([str(path), *PY36_ARGS])
-            with open(path, "r") as fh:
-                actual = fh.read()
+            actual = path.read_text(encoding="utf-8")
             # verify cache with --target-version is separate
-            py36_cache = black.read_cache(py36_mode)
-            self.assertIn(str(path), py36_cache)
-            normal_cache = black.read_cache(reg_mode)
-            self.assertNotIn(str(path), normal_cache)
+            py36_cache = black.Cache.read(py36_mode)
+            assert not py36_cache.is_changed(path)
+            normal_cache = black.Cache.read(reg_mode)
+            assert normal_cache.is_changed(path)
         self.assertEqual(actual, expected)
 
     @event_loop()
@@ -1139,26 +1207,24 @@ class BlackTestCase(BlackBaseTestCase):
                 (workspace / "file2.py").resolve(),
             ]
             for path in paths:
-                with open(path, "w") as fh:
-                    fh.write(source)
+                path.write_text(source, encoding="utf-8")
             self.invokeBlack([str(p) for p in paths] + PY36_ARGS)
             for path in paths:
-                with open(path, "r") as fh:
-                    actual = fh.read()
+                actual = path.read_text(encoding="utf-8")
                 self.assertEqual(actual, expected)
             # verify cache with --target-version is separate
-            pyi_cache = black.read_cache(py36_mode)
-            normal_cache = black.read_cache(reg_mode)
+            pyi_cache = black.Cache.read(py36_mode)
+            normal_cache = black.Cache.read(reg_mode)
             for path in paths:
-                self.assertIn(str(path), pyi_cache)
-                self.assertNotIn(str(path), normal_cache)
+                assert not pyi_cache.is_changed(path)
+                assert normal_cache.is_changed(path)
 
     def test_pipe_force_py36(self) -> None:
         source, expected = read_data("miscellaneous", "force_py36")
         result = CliRunner().invoke(
             black.main,
             ["-", "-q", "--target-version=py36"],
-            input=BytesIO(source.encode("utf8")),
+            input=BytesIO(source.encode("utf-8")),
         )
         self.assertEqual(result.exit_code, 0)
         actual = result.output
@@ -1281,8 +1347,51 @@ 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,
@@ -1344,11 +1453,11 @@ class BlackTestCase(BlackBaseTestCase):
             contents = nl.join(["def f(  ):", "    pass"])
             runner = BlackRunner()
             result = runner.invoke(
-                black.main, ["-", "--fast"], input=BytesIO(contents.encode("utf8"))
+                black.main, ["-", "--fast"], input=BytesIO(contents.encode("utf-8"))
             )
             self.assertEqual(result.exit_code, 0)
             output = result.stdout_bytes
-            self.assertIn(nl.encode("utf8"), output)
+            self.assertIn(nl.encode("utf-8"), output)
             if nl == "\n":
                 self.assertNotIn(b"\r\n", output)
 
@@ -1367,30 +1476,6 @@ class BlackTestCase(BlackBaseTestCase):
         with self.assertRaises(AssertionError):
             black.assert_equivalent("{}", "None")
 
-    def test_shhh_click(self) -> None:
-        try:
-            from click import _unicodefun  # type: ignore
-        except ImportError:
-            self.skipTest("Incompatible Click version")
-
-        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_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_python_env()
-            except RuntimeError as re:
-                self.fail(f"`patch_click()` failed, exception still raised: {re}")
-
     def test_root_logger_not_used_directly(self) -> None:
         def fail(*args: Any, **kwargs: Any) -> None:
             self.fail("Record created with root logger")
@@ -1429,6 +1514,85 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertEqual(config["exclude"], r"\.pyi?$")
         self.assertEqual(config["include"], r"\.py?$")
 
+    def test_parse_pyproject_toml_project_metadata(self) -> None:
+        for test_toml, expected in [
+            ("only_black_pyproject.toml", ["py310"]),
+            ("only_metadata_pyproject.toml", ["py37", "py38", "py39", "py310"]),
+            ("neither_pyproject.toml", None),
+            ("both_pyproject.toml", ["py310"]),
+        ]:
+            test_toml_file = THIS_DIR / "data" / "project_metadata" / test_toml
+            config = black.parse_pyproject_toml(str(test_toml_file))
+            self.assertEqual(config.get("target_version"), expected)
+
+    def test_infer_target_version(self) -> None:
+        for version, expected in [
+            ("3.6", [TargetVersion.PY36]),
+            ("3.11.0rc1", [TargetVersion.PY311]),
+            (">=3.10", [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312]),
+            (
+                ">=3.10.6",
+                [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312],
+            ),
+            ("<3.6", [TargetVersion.PY33, TargetVersion.PY34, TargetVersion.PY35]),
+            (">3.7,<3.10", [TargetVersion.PY38, TargetVersion.PY39]),
+            (
+                ">3.7,!=3.8,!=3.9",
+                [TargetVersion.PY310, TargetVersion.PY311, TargetVersion.PY312],
+            ),
+            (
+                "> 3.9.4, != 3.10.3",
+                [
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            (
+                "!=3.3,!=3.4",
+                [
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            (
+                "==3.*",
+                [
+                    TargetVersion.PY33,
+                    TargetVersion.PY34,
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                    TargetVersion.PY312,
+                ],
+            ),
+            ("==3.8.*", [TargetVersion.PY38]),
+            (None, None),
+            ("", None),
+            ("invalid", None),
+            ("==invalid", None),
+            (">3.9,!=invalid", None),
+            ("3", None),
+            ("3.2", None),
+            ("2.7.18", None),
+            ("==2.7", None),
+            (">3.10,<3.11", None),
+        ]:
+            test_toml = {"project": {"requires-python": version}}
+            result = black.files.infer_target_version(test_toml)
+            self.assertEqual(result, expected)
+
     def test_read_pyproject_toml(self) -> None:
         test_toml_file = THIS_DIR / "test.toml"
         fake_ctx = FakeContext()
@@ -1443,6 +1607,39 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertEqual(config["exclude"], r"\.pyi?$")
         self.assertEqual(config["include"], r"\.py?$")
 
+    def test_read_pyproject_toml_from_stdin(self) -> None:
+        with TemporaryDirectory() as workspace:
+            root = Path(workspace)
+
+            src_dir = root / "src"
+            src_dir.mkdir()
+
+            src_pyproject = src_dir / "pyproject.toml"
+            src_pyproject.touch()
+
+            test_toml_content = (THIS_DIR / "test.toml").read_text(encoding="utf-8")
+            src_pyproject.write_text(test_toml_content, encoding="utf-8")
+
+            src_python = src_dir / "foo.py"
+            src_python.touch()
+
+            fake_ctx = FakeContext()
+            fake_ctx.params["src"] = ("-",)
+            fake_ctx.params["stdin_filename"] = str(src_python)
+
+            with change_directory(root):
+                black.read_pyproject_toml(fake_ctx, FakeParameter(), None)
+
+            config = fake_ctx.default_map
+            self.assertEqual(config["verbose"], "1")
+            self.assertEqual(config["check"], "no")
+            self.assertEqual(config["diff"], "y")
+            self.assertEqual(config["color"], "True")
+            self.assertEqual(config["line_length"], "79")
+            self.assertEqual(config["target_version"], ["py36", "py37", "py38"])
+            self.assertEqual(config["exclude"], r"\.pyi?$")
+            self.assertEqual(config["include"], r"\.py?$")
+
     @pytest.mark.incompatible_with_mypyc
     def test_find_project_root(self) -> None:
         with TemporaryDirectory() as workspace:
@@ -1573,7 +1770,7 @@ class BlackTestCase(BlackBaseTestCase):
         tmp_file = Path(black.dump_to_file(source, ensure_final_newline=False))
         diff_header = re.compile(
             rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
-            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d \+\d\d\d\d"
+            r"\d\d:\d\d:\d\d\.\d\d\d\d\d\d\+\d\d:\d\d"
         )
         try:
             result = BlackRunner().invoke(black.main, ["--diff", str(tmp_file)])
@@ -1774,22 +1971,23 @@ class TestCaching:
         mode = DEFAULT_MODE
         with cache_dir() as workspace:
             cache_file = get_cache_file(mode)
-            cache_file.write_text("this is not a pickle")
-            assert black.read_cache(mode) == {}
+            cache_file.write_text("this is not a pickle", encoding="utf-8")
+            assert black.Cache.read(mode).file_data == {}
             src = (workspace / "test.py").resolve()
-            src.write_text("print('hello')")
+            src.write_text("print('hello')", encoding="utf-8")
             invokeBlack([str(src)])
-            cache = black.read_cache(mode)
-            assert str(src) in cache
+            cache = black.Cache.read(mode)
+            assert not cache.is_changed(src)
 
     def test_cache_single_file_already_cached(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
-            src.write_text("print('hello')")
-            black.write_cache({}, [src], mode)
+            src.write_text("print('hello')", encoding="utf-8")
+            cache = black.Cache.read(mode)
+            cache.write([src])
             invokeBlack([str(src)])
-            assert src.read_text() == "print('hello')"
+            assert src.read_text(encoding="utf-8") == "print('hello')"
 
     @event_loop()
     def test_cache_multiple_files(self) -> None:
@@ -1798,30 +1996,27 @@ class TestCaching:
             "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
             one = (workspace / "one.py").resolve()
-            with one.open("w") as fobj:
-                fobj.write("print('hello')")
+            one.write_text("print('hello')", encoding="utf-8")
             two = (workspace / "two.py").resolve()
-            with two.open("w") as fobj:
-                fobj.write("print('hello')")
-            black.write_cache({}, [one], mode)
+            two.write_text("print('hello')", encoding="utf-8")
+            cache = black.Cache.read(mode)
+            cache.write([one])
             invokeBlack([str(workspace)])
-            with one.open("r") as fobj:
-                assert fobj.read() == "print('hello')"
-            with two.open("r") as fobj:
-                assert fobj.read() == 'print("hello")\n'
-            cache = black.read_cache(mode)
-            assert str(one) in cache
-            assert str(two) in cache
+            assert one.read_text(encoding="utf-8") == "print('hello')"
+            assert two.read_text(encoding="utf-8") == 'print("hello")\n'
+            cache = black.Cache.read(mode)
+            assert not cache.is_changed(one)
+            assert not cache.is_changed(two)
 
+    @pytest.mark.incompatible_with_mypyc
     @pytest.mark.parametrize("color", [False, True], ids=["no-color", "with-color"])
     def test_no_cache_when_writeback_diff(self, color: bool) -> None:
         mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
-            with src.open("w") as fobj:
-                fobj.write("print('hello')")
-            with patch("black.read_cache") as read_cache, patch(
-                "black.write_cache"
+            src.write_text("print('hello')", encoding="utf-8")
+            with patch.object(black.Cache, "read") as read_cache, patch.object(
+                black.Cache, "write"
             ) as write_cache:
                 cmd = [str(src), "--diff"]
                 if color:
@@ -1829,8 +2024,8 @@ class TestCaching:
                 invokeBlack(cmd)
                 cache_file = get_cache_file(mode)
                 assert cache_file.exists() is False
+                read_cache.assert_called_once()
                 write_cache.assert_not_called()
-                read_cache.assert_not_called()
 
     @pytest.mark.parametrize("color", [False, True], ids=["no-color", "with-color"])
     @event_loop()
@@ -1838,8 +2033,7 @@ class TestCaching:
         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')")
+                src.write_text("print('hello')", encoding="utf-8")
             with patch(
                 "black.concurrency.Manager", wraps=multiprocessing.Manager
             ) as mgr:
@@ -1864,18 +2058,19 @@ class TestCaching:
     def test_read_cache_no_cachefile(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir():
-            assert black.read_cache(mode) == {}
+            assert black.Cache.read(mode).file_data == {}
 
     def test_write_cache_read_cache(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             src.touch()
-            black.write_cache({}, [src], mode)
-            cache = black.read_cache(mode)
-            assert str(src) in cache
-            assert cache[str(src)] == black.get_cache_info(src)
+            write_cache = black.Cache.read(mode)
+            write_cache.write([src])
+            read_cache = black.Cache.read(mode)
+            assert not read_cache.is_changed(src)
 
+    @pytest.mark.incompatible_with_mypyc
     def test_filter_cached(self) -> None:
         with TemporaryDirectory() as workspace:
             path = Path(workspace)
@@ -1885,21 +2080,67 @@ class TestCaching:
             uncached.touch()
             cached.touch()
             cached_but_changed.touch()
-            cache = {
-                str(cached): black.get_cache_info(cached),
-                str(cached_but_changed): (0.0, 0),
-            }
-            todo, done = black.cache.filter_cached(
-                cache, {uncached, cached, cached_but_changed}
-            )
+            cache = black.Cache.read(DEFAULT_MODE)
+
+            orig_func = black.Cache.get_file_data
+
+            def wrapped_func(path: Path) -> FileData:
+                if path == cached:
+                    return orig_func(path)
+                if path == cached_but_changed:
+                    return FileData(0.0, 0, "")
+                raise AssertionError
+
+            with patch.object(black.Cache, "get_file_data", side_effect=wrapped_func):
+                cache.write([cached, cached_but_changed])
+            todo, done = cache.filtered_cached({uncached, cached, cached_but_changed})
             assert todo == {uncached, cached_but_changed}
             assert done == {cached}
 
+    def test_filter_cached_hash(self) -> None:
+        with TemporaryDirectory() as workspace:
+            path = Path(workspace)
+            src = (path / "test.py").resolve()
+            src.write_text("print('hello')", encoding="utf-8")
+            st = src.stat()
+            cache = black.Cache.read(DEFAULT_MODE)
+            cache.write([src])
+            cached_file_data = cache.file_data[str(src)]
+
+            todo, done = cache.filtered_cached([src])
+            assert todo == set()
+            assert done == {src}
+            assert cached_file_data.st_mtime == st.st_mtime
+
+            # Modify st_mtime
+            cached_file_data = cache.file_data[str(src)] = FileData(
+                cached_file_data.st_mtime - 1,
+                cached_file_data.st_size,
+                cached_file_data.hash,
+            )
+            todo, done = cache.filtered_cached([src])
+            assert todo == set()
+            assert done == {src}
+            assert cached_file_data.st_mtime < st.st_mtime
+            assert cached_file_data.st_size == st.st_size
+            assert cached_file_data.hash == black.Cache.hash_digest(src)
+
+            # Modify contents
+            src.write_text("print('hello world')", encoding="utf-8")
+            new_st = src.stat()
+            todo, done = cache.filtered_cached([src])
+            assert todo == {src}
+            assert done == set()
+            assert cached_file_data.st_mtime < new_st.st_mtime
+            assert cached_file_data.st_size != new_st.st_size
+            assert cached_file_data.hash != black.Cache.hash_digest(src)
+
     def test_write_cache_creates_directory_if_needed(self) -> None:
         mode = DEFAULT_MODE
         with cache_dir(exists=False) as workspace:
             assert not workspace.exists()
-            black.write_cache({}, [], mode)
+            cache = black.Cache.read(mode)
+            cache.write([])
             assert workspace.exists()
 
     @event_loop()
@@ -1909,21 +2150,21 @@ class TestCaching:
             "concurrent.futures.ProcessPoolExecutor", new=ThreadPoolExecutor
         ):
             failing = (workspace / "failing.py").resolve()
-            with failing.open("w") as fobj:
-                fobj.write("not actually python")
+            failing.write_text("not actually python", encoding="utf-8")
             clean = (workspace / "clean.py").resolve()
-            with clean.open("w") as fobj:
-                fobj.write('print("hello")\n')
+            clean.write_text('print("hello")\n', encoding="utf-8")
             invokeBlack([str(workspace)], exit_code=123)
-            cache = black.read_cache(mode)
-            assert str(failing) not in cache
-            assert str(clean) in cache
+            cache = black.Cache.read(mode)
+            assert cache.is_changed(failing)
+            assert not cache.is_changed(clean)
 
     def test_write_cache_write_fail(self) -> None:
         mode = DEFAULT_MODE
-        with cache_dir(), patch.object(Path, "open") as mock:
-            mock.side_effect = OSError
-            black.write_cache({}, [], mode)
+        with cache_dir():
+            cache = black.Cache.read(mode)
+            with patch.object(Path, "open") as mock:
+                mock.side_effect = OSError
+                cache.write([])
 
     def test_read_cache_line_lengths(self) -> None:
         mode = DEFAULT_MODE
@@ -1931,18 +2172,19 @@ class TestCaching:
         with cache_dir() as workspace:
             path = (workspace / "file.py").resolve()
             path.touch()
-            black.write_cache({}, [path], mode)
-            one = black.read_cache(mode)
-            assert str(path) in one
-            two = black.read_cache(short_mode)
-            assert str(path) not in two
+            cache = black.Cache.read(mode)
+            cache.write([path])
+            one = black.Cache.read(mode)
+            assert not one.is_changed(path)
+            two = black.Cache.read(short_mode)
+            assert two.is_changed(path)
 
 
 def assert_collected_sources(
     src: Sequence[Union[str, Path]],
     expected: Sequence[Union[str, Path]],
     *,
-    ctx: Optional[FakeContext] = None,
+    root: Optional[Path] = None,
     exclude: Optional[str] = None,
     include: Optional[str] = None,
     extend_exclude: Optional[str] = None,
@@ -1958,7 +2200,7 @@ def assert_collected_sources(
     )
     gs_force_exclude = None if force_exclude is None else compile_pattern(force_exclude)
     collected = black.get_sources(
-        ctx=ctx or FakeContext(),
+        root=root or THIS_DIR,
         src=gs_src,
         quiet=False,
         verbose=False,
@@ -1994,9 +2236,16 @@ class TestFileCollection:
             base / "b/.definitely_exclude/a.pyi",
         ]
         src = [base / "b/"]
-        ctx = FakeContext()
-        ctx.obj["root"] = base
-        assert_collected_sources(src, expected, ctx=ctx, extend_exclude=r"/exclude/")
+        assert_collected_sources(src, expected, root=base, 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",
+        ]
+        src = [root / "dir1", root / "dir2"]
+        assert_collected_sources(src, expected, root=root)
 
     @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
     def test_exclude_for_issue_1572(self) -> None:
@@ -2031,7 +2280,7 @@ class TestFileCollection:
                 None,
                 None,
                 report,
-                gitignore,
+                {path: gitignore},
                 verbose=False,
                 quiet=False,
             )
@@ -2060,7 +2309,7 @@ class TestFileCollection:
                 None,
                 None,
                 report,
-                root_gitignore,
+                {path: root_gitignore},
                 verbose=False,
                 quiet=False,
             )
@@ -2098,6 +2347,26 @@ 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"]
+        assert_collected_sources([root], expected, root=root)
+
+        # If .gitignore with */* is nested
+        root = Path(DATA_DIR / "ignore_subfolders_gitignore_tests")
+        expected = [
+            root / "a.py",
+            root / "subdir" / "b.py",
+        ]
+        assert_collected_sources([root], expected, root=root)
+
+        # If command is executed from outer dir
+        root = Path(DATA_DIR / "ignore_subfolders_gitignore_tests")
+        target = root / "subdir"
+        expected = [target / "b.py"]
+        assert_collected_sources([target], expected, root=root)
+
     def test_empty_include(self) -> None:
         path = DATA_DIR / "include_exclude_tests"
         src = [path]
@@ -2129,38 +2398,48 @@ class TestFileCollection:
         )
 
     @pytest.mark.incompatible_with_mypyc
-    def test_symlink_out_of_root_directory(self) -> None:
+    def test_symlinks(self) -> None:
         path = MagicMock()
         root = THIS_DIR.resolve()
-        child = MagicMock()
         include = re.compile(black.DEFAULT_INCLUDES)
         exclude = re.compile(black.DEFAULT_EXCLUDES)
         report = black.Report()
         gitignore = PathSpec.from_lines("gitwildmatch", [])
-        # `child` should behave like a symlink which resolved path is clearly
-        # outside of the `root` directory.
-        path.iterdir.return_value = [child]
-        child.resolve.return_value = Path("/a/b/c")
-        child.as_posix.return_value = "/a/b/c"
-        try:
-            list(
-                black.gen_python_files(
-                    path.iterdir(),
-                    root,
-                    include,
-                    exclude,
-                    None,
-                    None,
-                    report,
-                    gitignore,
-                    verbose=False,
-                    quiet=False,
-                )
+
+        regular = MagicMock()
+        outside_root_symlink = MagicMock()
+        ignored_symlink = MagicMock()
+
+        path.iterdir.return_value = [regular, outside_root_symlink, ignored_symlink]
+
+        regular.absolute.return_value = root / "regular.py"
+        regular.resolve.return_value = root / "regular.py"
+        regular.is_dir.return_value = False
+
+        outside_root_symlink.absolute.return_value = root / "symlink.py"
+        outside_root_symlink.resolve.return_value = Path("/nowhere")
+
+        ignored_symlink.absolute.return_value = root / ".mypy_cache" / "symlink.py"
+
+        files = list(
+            black.gen_python_files(
+                path.iterdir(),
+                root,
+                include,
+                exclude,
+                None,
+                None,
+                report,
+                {path: gitignore},
+                verbose=False,
+                quiet=False,
             )
-        except ValueError as ve:
-            pytest.fail(f"`get_python_files_in_dir()` failed: {ve}")
+        )
+        assert files == [regular]
+
         path.iterdir.assert_called_once()
-        child.resolve.assert_called_once()
+        outside_root_symlink.resolve.assert_called_once()
+        ignored_symlink.resolve.assert_not_called()
 
     @patch("black.find_project_root", lambda *args: (THIS_DIR.resolve(), None))
     def test_get_sources_with_stdin(self) -> None:
@@ -2226,6 +2505,41 @@ class TestFileCollection:
         )
 
 
+class TestDeFactoAPI:
+    """Test that certain symbols that are commonly used externally keep working.
+
+    We don't (yet) formally expose an API (see issue #779), but we should endeavor to
+    keep certain functions that external users commonly rely on working.
+
+    """
+
+    def test_format_str(self) -> None:
+        # format_str and Mode should keep working
+        assert (
+            black.format_str("print('hello')", mode=black.Mode()) == 'print("hello")\n'
+        )
+
+        # you can pass line length
+        assert (
+            black.format_str("print('hello')", mode=black.Mode(line_length=42))
+            == 'print("hello")\n'
+        )
+
+        # invalid input raises InvalidInput
+        with pytest.raises(black.InvalidInput):
+            black.format_str("syntax error", mode=black.Mode())
+
+    def test_format_file_contents(self) -> None:
+        # You probably should be using format_str() instead, but let's keep
+        # this one around since people do use it
+        assert (
+            black.format_file_contents("x=1", fast=True, mode=black.Mode()) == "x = 1\n"
+        )
+
+        with pytest.raises(black.NothingChanged):
+            black.format_file_contents("x = 1\n", fast=True, mode=black.Mode())
+
+
 try:
     with open(black.__file__, "r", encoding="utf-8") as _bf:
         black_source_lines = _bf.readlines()