tests/test_black.py

   1 #!/usr/bin/env python3
   2 import asyncio
   3 from concurrent.futures import ThreadPoolExecutor
   4 from contextlib import contextmanager
   5 from functools import partial
   6 from io import StringIO
   7 import os
   8 from pathlib import Path
   9 import sys
  10 from tempfile import TemporaryDirectory
  11 from typing import Any, List, Tuple, Iterator
  12 import unittest
  13 from unittest.mock import patch
  14
  15 from click import unstyle
  16 from click.testing import CliRunner
  17
  18 import black
  19
  20 ll = 88
  21 ff = partial(black.format_file_in_place, line_length=ll, fast=True)
  22 fs = partial(black.format_str, line_length=ll)
  23 THIS_FILE = Path(__file__)
  24 THIS_DIR = THIS_FILE.parent
  25 EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
  26
  27
  28 def dump_to_stderr(*output: str) -> str:
  29     return "\n" + "\n".join(output) + "\n"
  30
  31
  32 def read_data(name: str) -> Tuple[str, str]:
  33     """read_data('test_name') -> 'input', 'output'"""
  34     if not name.endswith((".py", ".out", ".diff")):
  35         name += ".py"
  36     _input: List[str] = []
  37     _output: List[str] = []
  38     with open(THIS_DIR / name, "r", encoding="utf8") as test:
  39         lines = test.readlines()
  40     result = _input
  41     for line in lines:
  42         line = line.replace(EMPTY_LINE, "")
  43         if line.rstrip() == "# output":
  44             result = _output
  45             continue
  46
  47         result.append(line)
  48     if _input and not _output:
  49         # If there's no output marker, treat the entire file as already pre-formatted.
  50         _output = _input[:]
  51     return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
  52
  53
  54 @contextmanager
  55 def cache_dir(exists: bool = True) -> Iterator[Path]:
  56     with TemporaryDirectory() as workspace:
  57         cache_dir = Path(workspace)
  58         if not exists:
  59             cache_dir = cache_dir / "new"
  60         with patch("black.CACHE_DIR", cache_dir):
  61             yield cache_dir
  62
  63
  64 @contextmanager
  65 def event_loop(close: bool) -> Iterator[None]:
  66     policy = asyncio.get_event_loop_policy()
  67     old_loop = policy.get_event_loop()
  68     loop = policy.new_event_loop()
  69     asyncio.set_event_loop(loop)
  70     try:
  71         yield
  72
  73     finally:
  74         policy.set_event_loop(old_loop)
  75         if close:
  76             loop.close()
  77
  78
  79 class BlackTestCase(unittest.TestCase):
  80     maxDiff = None
  81
  82     def assertFormatEqual(self, expected: str, actual: str) -> None:
  83         if actual != expected and not os.environ.get("SKIP_AST_PRINT"):
  84             bdv: black.DebugVisitor[Any]
  85             black.out("Expected tree:", fg="green")
  86             try:
  87                 exp_node = black.lib2to3_parse(expected)
  88                 bdv = black.DebugVisitor()
  89                 list(bdv.visit(exp_node))
  90             except Exception as ve:
  91                 black.err(str(ve))
  92             black.out("Actual tree:", fg="red")
  93             try:
  94                 exp_node = black.lib2to3_parse(actual)
  95                 bdv = black.DebugVisitor()
  96                 list(bdv.visit(exp_node))
  97             except Exception as ve:
  98                 black.err(str(ve))
  99         self.assertEqual(expected, actual)
 100
 101     @patch("black.dump_to_file", dump_to_stderr)
 102     def test_self(self) -> None:
 103         source, expected = read_data("test_black")
 104         actual = fs(source)
 105         self.assertFormatEqual(expected, actual)
 106         black.assert_equivalent(source, actual)
 107         black.assert_stable(source, actual, line_length=ll)
 108         self.assertFalse(ff(THIS_FILE))
 109
 110     @patch("black.dump_to_file", dump_to_stderr)
 111     def test_black(self) -> None:
 112         source, expected = read_data("../black")
 113         actual = fs(source)
 114         self.assertFormatEqual(expected, actual)
 115         black.assert_equivalent(source, actual)
 116         black.assert_stable(source, actual, line_length=ll)
 117         self.assertFalse(ff(THIS_DIR / ".." / "black.py"))
 118
 119     def test_piping(self) -> None:
 120         source, expected = read_data("../black")
 121         hold_stdin, hold_stdout = sys.stdin, sys.stdout
 122         try:
 123             sys.stdin, sys.stdout = StringIO(source), StringIO()
 124             sys.stdin.name = "<stdin>"
 125             black.format_stdin_to_stdout(
 126                 line_length=ll, fast=True, write_back=black.WriteBack.YES
 127             )
 128             sys.stdout.seek(0)
 129             actual = sys.stdout.read()
 130         finally:
 131             sys.stdin, sys.stdout = hold_stdin, hold_stdout
 132         self.assertFormatEqual(expected, actual)
 133         black.assert_equivalent(source, actual)
 134         black.assert_stable(source, actual, line_length=ll)
 135
 136     def test_piping_diff(self) -> None:
 137         source, _ = read_data("expression.py")
 138         expected, _ = read_data("expression.diff")
 139         hold_stdin, hold_stdout = sys.stdin, sys.stdout
 140         try:
 141             sys.stdin, sys.stdout = StringIO(source), StringIO()
 142             sys.stdin.name = "<stdin>"
 143             black.format_stdin_to_stdout(
 144                 line_length=ll, fast=True, write_back=black.WriteBack.DIFF
 145             )
 146             sys.stdout.seek(0)
 147             actual = sys.stdout.read()
 148         finally:
 149             sys.stdin, sys.stdout = hold_stdin, hold_stdout
 150         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
 151         self.assertEqual(expected, actual)
 152
 153     @patch("black.dump_to_file", dump_to_stderr)
 154     def test_setup(self) -> None:
 155         source, expected = read_data("../setup")
 156         actual = fs(source)
 157         self.assertFormatEqual(expected, actual)
 158         black.assert_equivalent(source, actual)
 159         black.assert_stable(source, actual, line_length=ll)
 160         self.assertFalse(ff(THIS_DIR / ".." / "setup.py"))
 161
 162     @patch("black.dump_to_file", dump_to_stderr)
 163     def test_function(self) -> None:
 164         source, expected = read_data("function")
 165         actual = fs(source)
 166         self.assertFormatEqual(expected, actual)
 167         black.assert_equivalent(source, actual)
 168         black.assert_stable(source, actual, line_length=ll)
 169
 170     @patch("black.dump_to_file", dump_to_stderr)
 171     def test_function2(self) -> None:
 172         source, expected = read_data("function2")
 173         actual = fs(source)
 174         self.assertFormatEqual(expected, actual)
 175         black.assert_equivalent(source, actual)
 176         black.assert_stable(source, actual, line_length=ll)
 177
 178     @patch("black.dump_to_file", dump_to_stderr)
 179     def test_expression(self) -> None:
 180         source, expected = read_data("expression")
 181         actual = fs(source)
 182         self.assertFormatEqual(expected, actual)
 183         black.assert_equivalent(source, actual)
 184         black.assert_stable(source, actual, line_length=ll)
 185
 186     def test_expression_ff(self) -> None:
 187         source, expected = read_data("expression")
 188         tmp_file = Path(black.dump_to_file(source))
 189         try:
 190             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.YES))
 191             with open(tmp_file, encoding="utf8") as f:
 192                 actual = f.read()
 193         finally:
 194             os.unlink(tmp_file)
 195         self.assertFormatEqual(expected, actual)
 196         with patch("black.dump_to_file", dump_to_stderr):
 197             black.assert_equivalent(source, actual)
 198             black.assert_stable(source, actual, line_length=ll)
 199
 200     def test_expression_diff(self) -> None:
 201         source, _ = read_data("expression.py")
 202         expected, _ = read_data("expression.diff")
 203         tmp_file = Path(black.dump_to_file(source))
 204         hold_stdout = sys.stdout
 205         try:
 206             sys.stdout = StringIO()
 207             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.DIFF))
 208             sys.stdout.seek(0)
 209             actual = sys.stdout.read()
 210             actual = actual.replace(str(tmp_file), "<stdin>")
 211         finally:
 212             sys.stdout = hold_stdout
 213             os.unlink(tmp_file)
 214         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
 215         if expected != actual:
 216             dump = black.dump_to_file(actual)
 217             msg = (
 218                 f"Expected diff isn't equal to the actual. If you made changes "
 219                 f"to expression.py and this is an anticipated difference, "
 220                 f"overwrite tests/expression.diff with {dump}"
 221             )
 222             self.assertEqual(expected, actual, msg)
 223
 224     @patch("black.dump_to_file", dump_to_stderr)
 225     def test_fstring(self) -> None:
 226         source, expected = read_data("fstring")
 227         actual = fs(source)
 228         self.assertFormatEqual(expected, actual)
 229         black.assert_equivalent(source, actual)
 230         black.assert_stable(source, actual, line_length=ll)
 231
 232     @patch("black.dump_to_file", dump_to_stderr)
 233     def test_string_quotes(self) -> None:
 234         source, expected = read_data("string_quotes")
 235         actual = fs(source)
 236         self.assertFormatEqual(expected, actual)
 237         black.assert_equivalent(source, actual)
 238         black.assert_stable(source, actual, line_length=ll)
 239
 240     @patch("black.dump_to_file", dump_to_stderr)
 241     def test_slices(self) -> None:
 242         source, expected = read_data("slices")
 243         actual = fs(source)
 244         self.assertFormatEqual(expected, actual)
 245         black.assert_equivalent(source, actual)
 246         black.assert_stable(source, actual, line_length=ll)
 247
 248     @patch("black.dump_to_file", dump_to_stderr)
 249     def test_comments(self) -> None:
 250         source, expected = read_data("comments")
 251         actual = fs(source)
 252         self.assertFormatEqual(expected, actual)
 253         black.assert_equivalent(source, actual)
 254         black.assert_stable(source, actual, line_length=ll)
 255
 256     @patch("black.dump_to_file", dump_to_stderr)
 257     def test_comments2(self) -> None:
 258         source, expected = read_data("comments2")
 259         actual = fs(source)
 260         self.assertFormatEqual(expected, actual)
 261         black.assert_equivalent(source, actual)
 262         black.assert_stable(source, actual, line_length=ll)
 263
 264     @patch("black.dump_to_file", dump_to_stderr)
 265     def test_comments3(self) -> None:
 266         source, expected = read_data("comments3")
 267         actual = fs(source)
 268         self.assertFormatEqual(expected, actual)
 269         black.assert_equivalent(source, actual)
 270         black.assert_stable(source, actual, line_length=ll)
 271
 272     @patch("black.dump_to_file", dump_to_stderr)
 273     def test_comments4(self) -> None:
 274         source, expected = read_data("comments4")
 275         actual = fs(source)
 276         self.assertFormatEqual(expected, actual)
 277         black.assert_equivalent(source, actual)
 278         black.assert_stable(source, actual, line_length=ll)
 279
 280     @patch("black.dump_to_file", dump_to_stderr)
 281     def test_comments5(self) -> None:
 282         source, expected = read_data("comments5")
 283         actual = fs(source)
 284         self.assertFormatEqual(expected, actual)
 285         black.assert_equivalent(source, actual)
 286         black.assert_stable(source, actual, line_length=ll)
 287
 288     @patch("black.dump_to_file", dump_to_stderr)
 289     def test_cantfit(self) -> None:
 290         source, expected = read_data("cantfit")
 291         actual = fs(source)
 292         self.assertFormatEqual(expected, actual)
 293         black.assert_equivalent(source, actual)
 294         black.assert_stable(source, actual, line_length=ll)
 295
 296     @patch("black.dump_to_file", dump_to_stderr)
 297     def test_import_spacing(self) -> None:
 298         source, expected = read_data("import_spacing")
 299         actual = fs(source)
 300         self.assertFormatEqual(expected, actual)
 301         black.assert_equivalent(source, actual)
 302         black.assert_stable(source, actual, line_length=ll)
 303
 304     @patch("black.dump_to_file", dump_to_stderr)
 305     def test_composition(self) -> None:
 306         source, expected = read_data("composition")
 307         actual = fs(source)
 308         self.assertFormatEqual(expected, actual)
 309         black.assert_equivalent(source, actual)
 310         black.assert_stable(source, actual, line_length=ll)
 311
 312     @patch("black.dump_to_file", dump_to_stderr)
 313     def test_empty_lines(self) -> None:
 314         source, expected = read_data("empty_lines")
 315         actual = fs(source)
 316         self.assertFormatEqual(expected, actual)
 317         black.assert_equivalent(source, actual)
 318         black.assert_stable(source, actual, line_length=ll)
 319
 320     @patch("black.dump_to_file", dump_to_stderr)
 321     def test_string_prefixes(self) -> None:
 322         source, expected = read_data("string_prefixes")
 323         actual = fs(source)
 324         self.assertFormatEqual(expected, actual)
 325         black.assert_equivalent(source, actual)
 326         black.assert_stable(source, actual, line_length=ll)
 327
 328     @patch("black.dump_to_file", dump_to_stderr)
 329     def test_python2(self) -> None:
 330         source, expected = read_data("python2")
 331         actual = fs(source)
 332         self.assertFormatEqual(expected, actual)
 333         # black.assert_equivalent(source, actual)
 334         black.assert_stable(source, actual, line_length=ll)
 335
 336     @patch("black.dump_to_file", dump_to_stderr)
 337     def test_python2_unicode_literals(self) -> None:
 338         source, expected = read_data("python2_unicode_literals")
 339         actual = fs(source)
 340         self.assertFormatEqual(expected, actual)
 341         black.assert_stable(source, actual, line_length=ll)
 342
 343     @patch("black.dump_to_file", dump_to_stderr)
 344     def test_fmtonoff(self) -> None:
 345         source, expected = read_data("fmtonoff")
 346         actual = fs(source)
 347         self.assertFormatEqual(expected, actual)
 348         black.assert_equivalent(source, actual)
 349         black.assert_stable(source, actual, line_length=ll)
 350
 351     @patch("black.dump_to_file", dump_to_stderr)
 352     def test_remove_empty_parentheses_after_class(self) -> None:
 353         source, expected = read_data("class_blank_parentheses")
 354         actual = fs(source)
 355         self.assertFormatEqual(expected, actual)
 356         black.assert_equivalent(source, actual)
 357         black.assert_stable(source, actual, line_length=ll)
 358
 359     def test_report(self) -> None:
 360         report = black.Report()
 361         out_lines = []
 362         err_lines = []
 363
 364         def out(msg: str, **kwargs: Any) -> None:
 365             out_lines.append(msg)
 366
 367         def err(msg: str, **kwargs: Any) -> None:
 368             err_lines.append(msg)
 369
 370         with patch("black.out", out), patch("black.err", err):
 371             report.done(Path("f1"), black.Changed.NO)
 372             self.assertEqual(len(out_lines), 1)
 373             self.assertEqual(len(err_lines), 0)
 374             self.assertEqual(out_lines[-1], "f1 already well formatted, good job.")
 375             self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
 376             self.assertEqual(report.return_code, 0)
 377             report.done(Path("f2"), black.Changed.YES)
 378             self.assertEqual(len(out_lines), 2)
 379             self.assertEqual(len(err_lines), 0)
 380             self.assertEqual(out_lines[-1], "reformatted f2")
 381             self.assertEqual(
 382                 unstyle(str(report)), "1 file reformatted, 1 file left unchanged."
 383             )
 384             report.done(Path("f3"), black.Changed.CACHED)
 385             self.assertEqual(len(out_lines), 3)
 386             self.assertEqual(len(err_lines), 0)
 387             self.assertEqual(
 388                 out_lines[-1], "f3 wasn't modified on disk since last run."
 389             )
 390             self.assertEqual(
 391                 unstyle(str(report)), "1 file reformatted, 2 files left unchanged."
 392             )
 393             self.assertEqual(report.return_code, 0)
 394             report.check = True
 395             self.assertEqual(report.return_code, 1)
 396             report.check = False
 397             report.failed(Path("e1"), "boom")
 398             self.assertEqual(len(out_lines), 3)
 399             self.assertEqual(len(err_lines), 1)
 400             self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
 401             self.assertEqual(
 402                 unstyle(str(report)),
 403                 "1 file reformatted, 2 files left unchanged, "
 404                 "1 file failed to reformat.",
 405             )
 406             self.assertEqual(report.return_code, 123)
 407             report.done(Path("f3"), black.Changed.YES)
 408             self.assertEqual(len(out_lines), 4)
 409             self.assertEqual(len(err_lines), 1)
 410             self.assertEqual(out_lines[-1], "reformatted f3")
 411             self.assertEqual(
 412                 unstyle(str(report)),
 413                 "2 files reformatted, 2 files left unchanged, "
 414                 "1 file failed to reformat.",
 415             )
 416             self.assertEqual(report.return_code, 123)
 417             report.failed(Path("e2"), "boom")
 418             self.assertEqual(len(out_lines), 4)
 419             self.assertEqual(len(err_lines), 2)
 420             self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
 421             self.assertEqual(
 422                 unstyle(str(report)),
 423                 "2 files reformatted, 2 files left unchanged, "
 424                 "2 files failed to reformat.",
 425             )
 426             self.assertEqual(report.return_code, 123)
 427             report.done(Path("f4"), black.Changed.NO)
 428             self.assertEqual(len(out_lines), 5)
 429             self.assertEqual(len(err_lines), 2)
 430             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
 431             self.assertEqual(
 432                 unstyle(str(report)),
 433                 "2 files reformatted, 3 files left unchanged, "
 434                 "2 files failed to reformat.",
 435             )
 436             self.assertEqual(report.return_code, 123)
 437             report.check = True
 438             self.assertEqual(
 439                 unstyle(str(report)),
 440                 "2 files would be reformatted, 3 files would be left unchanged, "
 441                 "2 files would fail to reformat.",
 442             )
 443
 444     def test_is_python36(self) -> None:
 445         node = black.lib2to3_parse("def f(*, arg): ...\n")
 446         self.assertFalse(black.is_python36(node))
 447         node = black.lib2to3_parse("def f(*, arg,): ...\n")
 448         self.assertTrue(black.is_python36(node))
 449         node = black.lib2to3_parse("def f(*, arg): f'string'\n")
 450         self.assertTrue(black.is_python36(node))
 451         source, expected = read_data("function")
 452         node = black.lib2to3_parse(source)
 453         self.assertTrue(black.is_python36(node))
 454         node = black.lib2to3_parse(expected)
 455         self.assertTrue(black.is_python36(node))
 456         source, expected = read_data("expression")
 457         node = black.lib2to3_parse(source)
 458         self.assertFalse(black.is_python36(node))
 459         node = black.lib2to3_parse(expected)
 460         self.assertFalse(black.is_python36(node))
 461
 462     def test_get_future_imports(self) -> None:
 463         node = black.lib2to3_parse("\n")
 464         self.assertEqual(set(), black.get_future_imports(node))
 465         node = black.lib2to3_parse("from __future__ import black\n")
 466         self.assertEqual({"black"}, black.get_future_imports(node))
 467         node = black.lib2to3_parse("from __future__ import multiple, imports\n")
 468         self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
 469         node = black.lib2to3_parse("from __future__ import (parenthesized, imports)\n")
 470         self.assertEqual({"parenthesized", "imports"}, black.get_future_imports(node))
 471         node = black.lib2to3_parse(
 472             "from __future__ import multiple\nfrom __future__ import imports\n"
 473         )
 474         self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
 475         node = black.lib2to3_parse("# comment\nfrom __future__ import black\n")
 476         self.assertEqual({"black"}, black.get_future_imports(node))
 477         node = black.lib2to3_parse('"""docstring"""\nfrom __future__ import black\n')
 478         self.assertEqual({"black"}, black.get_future_imports(node))
 479         node = black.lib2to3_parse("some(other, code)\nfrom __future__ import black\n")
 480         self.assertEqual(set(), black.get_future_imports(node))
 481         node = black.lib2to3_parse("from some.module import black\n")
 482         self.assertEqual(set(), black.get_future_imports(node))
 483
 484     def test_debug_visitor(self) -> None:
 485         source, _ = read_data("debug_visitor.py")
 486         expected, _ = read_data("debug_visitor.out")
 487         out_lines = []
 488         err_lines = []
 489
 490         def out(msg: str, **kwargs: Any) -> None:
 491             out_lines.append(msg)
 492
 493         def err(msg: str, **kwargs: Any) -> None:
 494             err_lines.append(msg)
 495
 496         with patch("black.out", out), patch("black.err", err):
 497             black.DebugVisitor.show(source)
 498         actual = "\n".join(out_lines) + "\n"
 499         log_name = ""
 500         if expected != actual:
 501             log_name = black.dump_to_file(*out_lines)
 502         self.assertEqual(
 503             expected,
 504             actual,
 505             f"AST print out is different. Actual version dumped to {log_name}",
 506         )
 507
 508     def test_format_file_contents(self) -> None:
 509         empty = ""
 510         with self.assertRaises(black.NothingChanged):
 511             black.format_file_contents(empty, line_length=ll, fast=False)
 512         just_nl = "\n"
 513         with self.assertRaises(black.NothingChanged):
 514             black.format_file_contents(just_nl, line_length=ll, fast=False)
 515         same = "l = [1, 2, 3]\n"
 516         with self.assertRaises(black.NothingChanged):
 517             black.format_file_contents(same, line_length=ll, fast=False)
 518         different = "l = [1,2,3]"
 519         expected = same
 520         actual = black.format_file_contents(different, line_length=ll, fast=False)
 521         self.assertEqual(expected, actual)
 522         invalid = "return if you can"
 523         with self.assertRaises(ValueError) as e:
 524             black.format_file_contents(invalid, line_length=ll, fast=False)
 525         self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
 526
 527     def test_endmarker(self) -> None:
 528         n = black.lib2to3_parse("\n")
 529         self.assertEqual(n.type, black.syms.file_input)
 530         self.assertEqual(len(n.children), 1)
 531         self.assertEqual(n.children[0].type, black.token.ENDMARKER)
 532
 533     @unittest.skipIf(os.environ.get("SKIP_AST_PRINT"), "user set SKIP_AST_PRINT")
 534     def test_assertFormatEqual(self) -> None:
 535         out_lines = []
 536         err_lines = []
 537
 538         def out(msg: str, **kwargs: Any) -> None:
 539             out_lines.append(msg)
 540
 541         def err(msg: str, **kwargs: Any) -> None:
 542             err_lines.append(msg)
 543
 544         with patch("black.out", out), patch("black.err", err):
 545             with self.assertRaises(AssertionError):
 546                 self.assertFormatEqual("l = [1, 2, 3]", "l = [1, 2, 3,]")
 547
 548         out_str = "".join(out_lines)
 549         self.assertTrue("Expected tree:" in out_str)
 550         self.assertTrue("Actual tree:" in out_str)
 551         self.assertEqual("".join(err_lines), "")
 552
 553     def test_cache_broken_file(self) -> None:
 554         with cache_dir() as workspace:
 555             cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH)
 556             with cache_file.open("w") as fobj:
 557                 fobj.write("this is not a pickle")
 558             self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH), {})
 559             src = (workspace / "test.py").resolve()
 560             with src.open("w") as fobj:
 561                 fobj.write("print('hello')")
 562             result = CliRunner().invoke(black.main, [str(src)])
 563             self.assertEqual(result.exit_code, 0)
 564             cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
 565             self.assertIn(src, cache)
 566
 567     def test_cache_single_file_already_cached(self) -> None:
 568         with cache_dir() as workspace:
 569             src = (workspace / "test.py").resolve()
 570             with src.open("w") as fobj:
 571                 fobj.write("print('hello')")
 572             black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH)
 573             result = CliRunner().invoke(black.main, [str(src)])
 574             self.assertEqual(result.exit_code, 0)
 575             with src.open("r") as fobj:
 576                 self.assertEqual(fobj.read(), "print('hello')")
 577
 578     @event_loop(close=False)
 579     def test_cache_multiple_files(self) -> None:
 580         with cache_dir() as workspace, patch(
 581             "black.ProcessPoolExecutor", new=ThreadPoolExecutor
 582         ):
 583             one = (workspace / "one.py").resolve()
 584             with one.open("w") as fobj:
 585                 fobj.write("print('hello')")
 586             two = (workspace / "two.py").resolve()
 587             with two.open("w") as fobj:
 588                 fobj.write("print('hello')")
 589             black.write_cache({}, [one], black.DEFAULT_LINE_LENGTH)
 590             result = CliRunner().invoke(black.main, [str(workspace)])
 591             self.assertEqual(result.exit_code, 0)
 592             with one.open("r") as fobj:
 593                 self.assertEqual(fobj.read(), "print('hello')")
 594             with two.open("r") as fobj:
 595                 self.assertEqual(fobj.read(), 'print("hello")\n')
 596             cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
 597             self.assertIn(one, cache)
 598             self.assertIn(two, cache)
 599
 600     def test_no_cache_when_writeback_diff(self) -> None:
 601         with cache_dir() as workspace:
 602             src = (workspace / "test.py").resolve()
 603             with src.open("w") as fobj:
 604                 fobj.write("print('hello')")
 605             result = CliRunner().invoke(black.main, [str(src), "--diff"])
 606             self.assertEqual(result.exit_code, 0)
 607             cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH)
 608             self.assertFalse(cache_file.exists())
 609
 610     def test_no_cache_when_stdin(self) -> None:
 611         with cache_dir():
 612             result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
 613             self.assertEqual(result.exit_code, 0)
 614             cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH)
 615             self.assertFalse(cache_file.exists())
 616
 617     def test_read_cache_no_cachefile(self) -> None:
 618         with cache_dir():
 619             self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH), {})
 620
 621     def test_write_cache_read_cache(self) -> None:
 622         with cache_dir() as workspace:
 623             src = (workspace / "test.py").resolve()
 624             src.touch()
 625             black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH)
 626             cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
 627             self.assertIn(src, cache)
 628             self.assertEqual(cache[src], black.get_cache_info(src))
 629
 630     def test_filter_cached(self) -> None:
 631         with TemporaryDirectory() as workspace:
 632             path = Path(workspace)
 633             uncached = (path / "uncached").resolve()
 634             cached = (path / "cached").resolve()
 635             cached_but_changed = (path / "changed").resolve()
 636             uncached.touch()
 637             cached.touch()
 638             cached_but_changed.touch()
 639             cache = {cached: black.get_cache_info(cached), cached_but_changed: (0.0, 0)}
 640             todo, done = black.filter_cached(
 641                 cache, [uncached, cached, cached_but_changed]
 642             )
 643             self.assertEqual(todo, [uncached, cached_but_changed])
 644             self.assertEqual(done, [cached])
 645
 646     def test_write_cache_creates_directory_if_needed(self) -> None:
 647         with cache_dir(exists=False) as workspace:
 648             self.assertFalse(workspace.exists())
 649             black.write_cache({}, [], black.DEFAULT_LINE_LENGTH)
 650             self.assertTrue(workspace.exists())
 651
 652     @event_loop(close=False)
 653     def test_failed_formatting_does_not_get_cached(self) -> None:
 654         with cache_dir() as workspace, patch(
 655             "black.ProcessPoolExecutor", new=ThreadPoolExecutor
 656         ):
 657             failing = (workspace / "failing.py").resolve()
 658             with failing.open("w") as fobj:
 659                 fobj.write("not actually python")
 660             clean = (workspace / "clean.py").resolve()
 661             with clean.open("w") as fobj:
 662                 fobj.write('print("hello")\n')
 663             result = CliRunner().invoke(black.main, [str(workspace)])
 664             self.assertEqual(result.exit_code, 123)
 665             cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
 666             self.assertNotIn(failing, cache)
 667             self.assertIn(clean, cache)
 668
 669     def test_write_cache_write_fail(self) -> None:
 670         with cache_dir(), patch.object(Path, "open") as mock:
 671             mock.side_effect = OSError
 672             black.write_cache({}, [], black.DEFAULT_LINE_LENGTH)
 673
 674     def test_check_diff_use_together(self) -> None:
 675         with cache_dir():
 676             # Files which will be reformatted.
 677             src1 = (THIS_DIR / "string_quotes.py").resolve()
 678             result = CliRunner().invoke(black.main, [str(src1), "--diff", "--check"])
 679             self.assertEqual(result.exit_code, 1)
 680
 681             # Files which will not be reformatted.
 682             src2 = (THIS_DIR / "composition.py").resolve()
 683             result = CliRunner().invoke(black.main, [str(src2), "--diff", "--check"])
 684             self.assertEqual(result.exit_code, 0)
 685
 686             # Multi file command.
 687             result = CliRunner().invoke(
 688                 black.main, [str(src1), str(src2), "--diff", "--check"]
 689             )
 690             self.assertEqual(result.exit_code, 1)
 691
 692     def test_no_files(self) -> None:
 693         with cache_dir():
 694             # Without an argument, black exits with error code 0.
 695             result = CliRunner().invoke(black.main, [])
 696             self.assertEqual(result.exit_code, 0)
 697
 698     def test_read_cache_line_lengths(self) -> None:
 699         with cache_dir() as workspace:
 700             path = (workspace / "file.py").resolve()
 701             path.touch()
 702             black.write_cache({}, [path], 1)
 703             one = black.read_cache(1)
 704             self.assertIn(path, one)
 705             two = black.read_cache(2)
 706             self.assertNotIn(path, two)
 707
 708
 709 if __name__ == "__main__":
 710     unittest.main()