Change tests with stdin/out to exercise black.main (#307)

[etc/vim.git] / tests / test_black.py

diff --git a/tests/test_black.py b/tests/test_black.py
index b4820531fab62d860808b37448881ccf3b494a78..1271290d9497244b041efba17987800fb33f2cc3 100644 (file)
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -1,13 +1,15 @@
 #!/usr/bin/env python3
 import asyncio
 #!/usr/bin/env python3
 import asyncio

+from concurrent.futures import ThreadPoolExecutor

 from contextlib import contextmanager
 from functools import partial
 from contextlib import contextmanager
 from functools import partial

-from io import StringIO
+from io import BytesIO, TextIOWrapper

 import os
 from pathlib import Path
 import os
 from pathlib import Path

+import re

 import sys
 from tempfile import TemporaryDirectory
 import sys
 from tempfile import TemporaryDirectory

-from typing import Any, List, Tuple, Iterator
+from typing import Any, BinaryIO, Generator, List, Tuple, Iterator

 import unittest
 from unittest.mock import patch
 
 import unittest
 from unittest.mock import patch
 


@@ -16,6 +18,7 @@ from click.testing import CliRunner
 
 import black
 
 
 import black
 

+

 ll = 88
 ff = partial(black.format_file_in_place, line_length=ll, fast=True)
 fs = partial(black.format_str, line_length=ll)
 ll = 88
 ff = partial(black.format_file_in_place, line_length=ll, fast=True)
 fs = partial(black.format_str, line_length=ll)


@@ -30,7 +33,7 @@ def dump_to_stderr(*output: str) -> str:
 
 def read_data(name: str) -> Tuple[str, str]:
     """read_data('test_name') -> 'input', 'output'"""
 
 def read_data(name: str) -> Tuple[str, str]:
     """read_data('test_name') -> 'input', 'output'"""

-    if not name.endswith((".py", ".out", ".diff")):
+    if not name.endswith((".py", ".pyi", ".out", ".diff")):

         name += ".py"
     _input: List[str] = []
     _output: List[str] = []
         name += ".py"
     _input: List[str] = []
     _output: List[str] = []


@@ -56,8 +59,7 @@ def cache_dir(exists: bool = True) -> Iterator[Path]:
         cache_dir = Path(workspace)
         if not exists:
             cache_dir = cache_dir / "new"
         cache_dir = Path(workspace)
         if not exists:
             cache_dir = cache_dir / "new"

-        cache_file = cache_dir / "cache.pkl"
-        with patch("black.CACHE_DIR", cache_dir), patch("black.CACHE_FILE", cache_file):
+        with patch("black.CACHE_DIR", cache_dir):

             yield cache_dir
 
 
             yield cache_dir
 
 


@@ -76,6 +78,26 @@ def event_loop(close: bool) -> Iterator[None]:
             loop.close()
 
 
             loop.close()
 
 

+class BlackRunner(CliRunner):
+    """Modify CliRunner so that stderr is not merged with stdout.
+
+    This is a hack that can be removed once we depend on Click 7.x"""
+
+    def __init__(self, stderrbuf: BinaryIO) -> None:
+        self.stderrbuf = stderrbuf
+        super().__init__()
+
+    @contextmanager
+    def isolation(self, *args: Any, **kwargs: Any) -> Generator[BinaryIO, None, None]:
+        with super().isolation(*args, **kwargs) as output:
+            try:
+                hold_stderr = sys.stderr
+                sys.stderr = TextIOWrapper(self.stderrbuf, encoding=self.charset)
+                yield output
+            finally:
+                sys.stderr = hold_stderr
+
+

 class BlackTestCase(unittest.TestCase):
     maxDiff = None
 
 class BlackTestCase(unittest.TestCase):
     maxDiff = None
 


@@ -98,6 +120,25 @@ class BlackTestCase(unittest.TestCase):
                 black.err(str(ve))
         self.assertEqual(expected, actual)
 
                 black.err(str(ve))
         self.assertEqual(expected, actual)
 

+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_empty(self) -> None:
+        source = expected = ""
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+
+    def test_empty_ff(self) -> None:
+        expected = ""
+        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()
+        finally:
+            os.unlink(tmp_file)
+        self.assertFormatEqual(expected, actual)
+

     @patch("black.dump_to_file", dump_to_stderr)
     def test_self(self) -> None:
         source, expected = read_data("test_black")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_self(self) -> None:
         source, expected = read_data("test_black")


@@ -118,35 +159,28 @@ class BlackTestCase(unittest.TestCase):
 
     def test_piping(self) -> None:
         source, expected = read_data("../black")
 
     def test_piping(self) -> None:
         source, expected = read_data("../black")

-        hold_stdin, hold_stdout = sys.stdin, sys.stdout
-        try:
-            sys.stdin, sys.stdout = StringIO(source), StringIO()
-            sys.stdin.name = "<stdin>"
-            black.format_stdin_to_stdout(
-                line_length=ll, fast=True, write_back=black.WriteBack.YES
-            )
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
-        finally:
-            sys.stdin, sys.stdout = hold_stdin, hold_stdout
-        self.assertFormatEqual(expected, actual)
-        black.assert_equivalent(source, actual)
-        black.assert_stable(source, actual, line_length=ll)
+        stderrbuf = BytesIO()
+        result = BlackRunner(stderrbuf).invoke(
+            black.main, ["-", "--fast", f"--line-length={ll}"], input=source
+        )
+        self.assertEqual(result.exit_code, 0)
+        self.assertFormatEqual(expected, result.output)
+        black.assert_equivalent(source, result.output)
+        black.assert_stable(source, result.output, line_length=ll)

 
     def test_piping_diff(self) -> None:
 
     def test_piping_diff(self) -> None:

+        diff_header = re.compile(
+            rf"(STDIN|STDOUT)\t\d\d\d\d-\d\d-\d\d "
+            rf"\d\d:\d\d:\d\d\.\d\d\d\d\d\d \+\d\d\d\d"
+        )

         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")
         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")

-        hold_stdin, hold_stdout = sys.stdin, sys.stdout
-        try:
-            sys.stdin, sys.stdout = StringIO(source), StringIO()
-            sys.stdin.name = "<stdin>"
-            black.format_stdin_to_stdout(
-                line_length=ll, fast=True, write_back=black.WriteBack.DIFF
-            )
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
-        finally:
-            sys.stdin, sys.stdout = hold_stdin, hold_stdout
+        stderrbuf = BytesIO()
+        result = BlackRunner(stderrbuf).invoke(
+            black.main, ["-", "--fast", f"--line-length={ll}", "--diff"], input=source
+        )
+        self.assertEqual(result.exit_code, 0)
+        actual = diff_header.sub("[Deterministic header]", result.output)

         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
         self.assertEqual(expected, actual)
 
         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
         self.assertEqual(expected, actual)
 


@@ -167,6 +201,14 @@ class BlackTestCase(unittest.TestCase):
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 

+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_function2(self) -> None:
+        source, expected = read_data("function2")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+

     @patch("black.dump_to_file", dump_to_stderr)
     def test_expression(self) -> None:
         source, expected = read_data("expression")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_expression(self) -> None:
         source, expected = read_data("expression")


@@ -193,16 +235,20 @@ class BlackTestCase(unittest.TestCase):
         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")
         tmp_file = Path(black.dump_to_file(source))
         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")
         tmp_file = Path(black.dump_to_file(source))

-        hold_stdout = sys.stdout
+        diff_header = re.compile(
+            rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
+            rf"\d\d:\d\d:\d\d\.\d\d\d\d\d\d \+\d\d\d\d"
+        )
+        stderrbuf = BytesIO()

         try:
         try:

-            sys.stdout = StringIO()
-            self.assertTrue(ff(tmp_file, write_back=black.WriteBack.DIFF))
-            sys.stdout.seek(0)
-            actual = sys.stdout.read()
-            actual = actual.replace(tmp_file.name, "<stdin>")
+            result = BlackRunner(stderrbuf).invoke(
+                black.main, ["--diff", str(tmp_file)]
+            )
+            self.assertEqual(result.exit_code, 0)

         finally:
         finally:

-            sys.stdout = hold_stdout

             os.unlink(tmp_file)
             os.unlink(tmp_file)

+        actual = result.output
+        actual = diff_header.sub("[Deterministic header]", actual)

         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
         if expected != actual:
             dump = black.dump_to_file(actual)
         actual = actual.rstrip() + "\n"  # the diff output has a trailing space
         if expected != actual:
             dump = black.dump_to_file(actual)


@@ -228,6 +274,19 @@ class BlackTestCase(unittest.TestCase):
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
         self.assertFormatEqual(expected, actual)
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)

+        mode = black.FileMode.NO_STRING_NORMALIZATION
+        not_normalized = fs(source, mode=mode)
+        self.assertFormatEqual(source, not_normalized)
+        black.assert_equivalent(source, not_normalized)
+        black.assert_stable(source, not_normalized, line_length=ll, mode=mode)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_slices(self) -> None:
+        source, expected = read_data("slices")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)

 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments(self) -> None:
 
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments(self) -> None:


@@ -261,6 +320,14 @@ class BlackTestCase(unittest.TestCase):
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 

+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_comments5(self) -> None:
+        source, expected = read_data("comments5")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+

     @patch("black.dump_to_file", dump_to_stderr)
     def test_cantfit(self) -> None:
         source, expected = read_data("cantfit")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_cantfit(self) -> None:
         source, expected = read_data("cantfit")


@@ -293,6 +360,14 @@ class BlackTestCase(unittest.TestCase):
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 

+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_string_prefixes(self) -> None:
+        source, expected = read_data("string_prefixes")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+

     @patch("black.dump_to_file", dump_to_stderr)
     def test_python2(self) -> None:
         source, expected = read_data("python2")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_python2(self) -> None:
         source, expected = read_data("python2")


@@ -301,6 +376,21 @@ class BlackTestCase(unittest.TestCase):
         # black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 
         # black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 

+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_python2_unicode_literals(self) -> None:
+        source, expected = read_data("python2_unicode_literals")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_stable(source, actual, line_length=ll)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_stub(self) -> None:
+        mode = black.FileMode.PYI
+        source, expected = read_data("stub.pyi")
+        actual = fs(source, mode=mode)
+        self.assertFormatEqual(expected, actual)
+        black.assert_stable(source, actual, line_length=ll, mode=mode)
+

     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff(self) -> None:
         source, expected = read_data("fmtonoff")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_fmtonoff(self) -> None:
         source, expected = read_data("fmtonoff")


@@ -309,8 +399,24 @@ class BlackTestCase(unittest.TestCase):
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 
         black.assert_equivalent(source, actual)
         black.assert_stable(source, actual, line_length=ll)
 

-    def test_report(self) -> None:
-        report = black.Report()
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_remove_empty_parentheses_after_class(self) -> None:
+        source, expected = read_data("class_blank_parentheses")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_new_line_between_class_and_code(self) -> None:
+        source, expected = read_data("class_methods_new_line")
+        actual = fs(source)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll)
+
+    def test_report_verbose(self) -> None:
+        report = black.Report(verbose=True)

         out_lines = []
         err_lines = []
 
         out_lines = []
         err_lines = []
 


@@ -377,9 +483,19 @@ class BlackTestCase(unittest.TestCase):
                 "2 files failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
                 "2 files failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)

-            report.done(Path("f4"), black.Changed.NO)
+            report.path_ignored(Path("wat"), "no match")

             self.assertEqual(len(out_lines), 5)
             self.assertEqual(len(err_lines), 2)
             self.assertEqual(len(out_lines), 5)
             self.assertEqual(len(err_lines), 2)

+            self.assertEqual(out_lines[-1], "wat ignored: no match")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 6)
+            self.assertEqual(len(err_lines), 2)

             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
             self.assertEqual(
                 unstyle(str(report)),
             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
             self.assertEqual(
                 unstyle(str(report)),


@@ -394,6 +510,183 @@ class BlackTestCase(unittest.TestCase):
                 "2 files would fail to reformat.",
             )
 
                 "2 files would fail to reformat.",
             )
 

+    def test_report_quiet(self) -> None:
+        report = black.Report(quiet=True)
+        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.out", out), patch("black.err", err):
+            report.done(Path("f1"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
+            self.assertEqual(report.return_code, 0)
+            report.done(Path("f2"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 1 file left unchanged."
+            )
+            report.done(Path("f3"), black.Changed.CACHED)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 2 files left unchanged."
+            )
+            self.assertEqual(report.return_code, 0)
+            report.check = True
+            self.assertEqual(report.return_code, 1)
+            report.check = False
+            report.failed(Path("e1"), "boom")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "1 file reformatted, 2 files left unchanged, "
+                "1 file failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f3"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "1 file failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.failed(Path("e2"), "boom")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.path_ignored(Path("wat"), "no match")
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 3 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.check = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, "
+                "2 files would fail to reformat.",
+            )
+
+    def test_report_normal(self) -> None:
+        report = black.Report()
+        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.out", out), patch("black.err", err):
+            report.done(Path("f1"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 0)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
+            self.assertEqual(report.return_code, 0)
+            report.done(Path("f2"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(out_lines[-1], "reformatted f2")
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 1 file left unchanged."
+            )
+            report.done(Path("f3"), black.Changed.CACHED)
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(out_lines[-1], "reformatted f2")
+            self.assertEqual(
+                unstyle(str(report)), "1 file reformatted, 2 files left unchanged."
+            )
+            self.assertEqual(report.return_code, 0)
+            report.check = True
+            self.assertEqual(report.return_code, 1)
+            report.check = False
+            report.failed(Path("e1"), "boom")
+            self.assertEqual(len(out_lines), 1)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "1 file reformatted, 2 files left unchanged, "
+                "1 file failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f3"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 1)
+            self.assertEqual(out_lines[-1], "reformatted f3")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "1 file failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.failed(Path("e2"), "boom")
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.path_ignored(Path("wat"), "no match")
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 2 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 2)
+            self.assertEqual(len(err_lines), 2)
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files reformatted, 3 files left unchanged, "
+                "2 files failed to reformat.",
+            )
+            self.assertEqual(report.return_code, 123)
+            report.check = True
+            self.assertEqual(
+                unstyle(str(report)),
+                "2 files would be reformatted, 3 files would be left unchanged, "
+                "2 files would fail to reformat.",
+            )
+

     def test_is_python36(self) -> None:
         node = black.lib2to3_parse("def f(*, arg): ...\n")
         self.assertFalse(black.is_python36(node))
     def test_is_python36(self) -> None:
         node = black.lib2to3_parse("def f(*, arg): ...\n")
         self.assertFalse(black.is_python36(node))


@@ -412,6 +705,28 @@ class BlackTestCase(unittest.TestCase):
         node = black.lib2to3_parse(expected)
         self.assertFalse(black.is_python36(node))
 
         node = black.lib2to3_parse(expected)
         self.assertFalse(black.is_python36(node))
 

+    def test_get_future_imports(self) -> None:
+        node = black.lib2to3_parse("\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import black\n")
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import multiple, imports\n")
+        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("from __future__ import (parenthesized, imports)\n")
+        self.assertEqual({"parenthesized", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse(
+            "from __future__ import multiple\nfrom __future__ import imports\n"
+        )
+        self.assertEqual({"multiple", "imports"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("# comment\nfrom __future__ import black\n")
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse('"""docstring"""\nfrom __future__ import black\n')
+        self.assertEqual({"black"}, black.get_future_imports(node))
+        node = black.lib2to3_parse("some(other, code)\nfrom __future__ import black\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+        node = black.lib2to3_parse("from some.module import black\n")
+        self.assertEqual(set(), black.get_future_imports(node))
+

     def test_debug_visitor(self) -> None:
         source, _ = read_data("debug_visitor.py")
         expected, _ = read_data("debug_visitor.out")
     def test_debug_visitor(self) -> None:
         source, _ = read_data("debug_visitor.py")
         expected, _ = read_data("debug_visitor.out")


@@ -482,24 +797,27 @@ class BlackTestCase(unittest.TestCase):
         self.assertEqual("".join(err_lines), "")
 
     def test_cache_broken_file(self) -> None:
         self.assertEqual("".join(err_lines), "")
 
     def test_cache_broken_file(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir() as workspace:
         with cache_dir() as workspace:

-            with black.CACHE_FILE.open("w") as fobj:
+            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
+            with cache_file.open("w") as fobj:

                 fobj.write("this is not a pickle")
                 fobj.write("this is not a pickle")

-            self.assertEqual(black.read_cache(), {})
+            self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH, mode), {})

             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
             result = CliRunner().invoke(black.main, [str(src)])
             self.assertEqual(result.exit_code, 0)
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
             result = CliRunner().invoke(black.main, [str(src)])
             self.assertEqual(result.exit_code, 0)

-            cache = black.read_cache()
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)

             self.assertIn(src, cache)
 
     def test_cache_single_file_already_cached(self) -> None:
             self.assertIn(src, cache)
 
     def test_cache_single_file_already_cached(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")

-            black.write_cache({}, [src])
+            black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH, mode)

             result = CliRunner().invoke(black.main, [str(src)])
             self.assertEqual(result.exit_code, 0)
             with src.open("r") as fobj:
             result = CliRunner().invoke(black.main, [str(src)])
             self.assertEqual(result.exit_code, 0)
             with src.open("r") as fobj:


@@ -507,49 +825,58 @@ class BlackTestCase(unittest.TestCase):
 
     @event_loop(close=False)
     def test_cache_multiple_files(self) -> None:
 
     @event_loop(close=False)
     def test_cache_multiple_files(self) -> None:

-        with cache_dir() as workspace:
+        mode = black.FileMode.AUTO_DETECT
+        with cache_dir() as workspace, patch(
+            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
+        ):

             one = (workspace / "one.py").resolve()
             with one.open("w") as fobj:
                 fobj.write("print('hello')")
             two = (workspace / "two.py").resolve()
             with two.open("w") as fobj:
                 fobj.write("print('hello')")
             one = (workspace / "one.py").resolve()
             with one.open("w") as fobj:
                 fobj.write("print('hello')")
             two = (workspace / "two.py").resolve()
             with two.open("w") as fobj:
                 fobj.write("print('hello')")

-            black.write_cache({}, [one])
+            black.write_cache({}, [one], black.DEFAULT_LINE_LENGTH, mode)

             result = CliRunner().invoke(black.main, [str(workspace)])
             self.assertEqual(result.exit_code, 0)
             with one.open("r") as fobj:
                 self.assertEqual(fobj.read(), "print('hello')")
             with two.open("r") as fobj:
                 self.assertEqual(fobj.read(), 'print("hello")\n')
             result = CliRunner().invoke(black.main, [str(workspace)])
             self.assertEqual(result.exit_code, 0)
             with one.open("r") as fobj:
                 self.assertEqual(fobj.read(), "print('hello')")
             with two.open("r") as fobj:
                 self.assertEqual(fobj.read(), 'print("hello")\n')

-            cache = black.read_cache()
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)

             self.assertIn(one, cache)
             self.assertIn(two, cache)
 
     def test_no_cache_when_writeback_diff(self) -> None:
             self.assertIn(one, cache)
             self.assertIn(two, cache)
 
     def test_no_cache_when_writeback_diff(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
             result = CliRunner().invoke(black.main, [str(src), "--diff"])
             self.assertEqual(result.exit_code, 0)
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
             result = CliRunner().invoke(black.main, [str(src), "--diff"])
             self.assertEqual(result.exit_code, 0)

-            self.assertFalse(black.CACHE_FILE.exists())
+            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
+            self.assertFalse(cache_file.exists())

 
     def test_no_cache_when_stdin(self) -> None:
 
     def test_no_cache_when_stdin(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir():
             result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
             self.assertEqual(result.exit_code, 0)
         with cache_dir():
             result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
             self.assertEqual(result.exit_code, 0)

-            self.assertFalse(black.CACHE_FILE.exists())
+            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
+            self.assertFalse(cache_file.exists())

 
     def test_read_cache_no_cachefile(self) -> None:
 
     def test_read_cache_no_cachefile(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir():
         with cache_dir():

-            self.assertEqual(black.read_cache(), {})
+            self.assertEqual(black.read_cache(black.DEFAULT_LINE_LENGTH, mode), {})

 
     def test_write_cache_read_cache(self) -> None:
 
     def test_write_cache_read_cache(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             src.touch()
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             src.touch()

-            black.write_cache({}, [src])
-            cache = black.read_cache()
+            black.write_cache({}, [src], black.DEFAULT_LINE_LENGTH, mode)
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)

             self.assertIn(src, cache)
             self.assertEqual(cache[src], black.get_cache_info(src))
 
             self.assertIn(src, cache)
             self.assertEqual(cache[src], black.get_cache_info(src))
 


@@ -564,20 +891,24 @@ class BlackTestCase(unittest.TestCase):
             cached_but_changed.touch()
             cache = {cached: black.get_cache_info(cached), cached_but_changed: (0.0, 0)}
             todo, done = black.filter_cached(
             cached_but_changed.touch()
             cache = {cached: black.get_cache_info(cached), cached_but_changed: (0.0, 0)}
             todo, done = black.filter_cached(

-                cache, [uncached, cached, cached_but_changed]
+                cache, {uncached, cached, cached_but_changed}

             )
             )

-            self.assertEqual(todo, [uncached, cached_but_changed])
-            self.assertEqual(done, [cached])
+            self.assertEqual(todo, {uncached, cached_but_changed})
+            self.assertEqual(done, {cached})

 
     def test_write_cache_creates_directory_if_needed(self) -> None:
 
     def test_write_cache_creates_directory_if_needed(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir(exists=False) as workspace:
             self.assertFalse(workspace.exists())
         with cache_dir(exists=False) as workspace:
             self.assertFalse(workspace.exists())

-            black.write_cache({}, [])
+            black.write_cache({}, [], black.DEFAULT_LINE_LENGTH, mode)

             self.assertTrue(workspace.exists())
 
     @event_loop(close=False)
     def test_failed_formatting_does_not_get_cached(self) -> None:
             self.assertTrue(workspace.exists())
 
     @event_loop(close=False)
     def test_failed_formatting_does_not_get_cached(self) -> None:

-        with cache_dir() as workspace:
+        mode = black.FileMode.AUTO_DETECT
+        with cache_dir() as workspace, patch(
+            "black.ProcessPoolExecutor", new=ThreadPoolExecutor
+        ):

             failing = (workspace / "failing.py").resolve()
             with failing.open("w") as fobj:
                 fobj.write("not actually python")
             failing = (workspace / "failing.py").resolve()
             with failing.open("w") as fobj:
                 fobj.write("not actually python")


@@ -586,15 +917,17 @@ class BlackTestCase(unittest.TestCase):
                 fobj.write('print("hello")\n')
             result = CliRunner().invoke(black.main, [str(workspace)])
             self.assertEqual(result.exit_code, 123)
                 fobj.write('print("hello")\n')
             result = CliRunner().invoke(black.main, [str(workspace)])
             self.assertEqual(result.exit_code, 123)

-            cache = black.read_cache()
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH, mode)

             self.assertNotIn(failing, cache)
             self.assertIn(clean, cache)
 
     def test_write_cache_write_fail(self) -> None:
             self.assertNotIn(failing, cache)
             self.assertIn(clean, cache)
 
     def test_write_cache_write_fail(self) -> None:

+        mode = black.FileMode.AUTO_DETECT

         with cache_dir(), patch.object(Path, "open") as mock:
             mock.side_effect = OSError
         with cache_dir(), patch.object(Path, "open") as mock:
             mock.side_effect = OSError

-            black.write_cache({}, [])
+            black.write_cache({}, [], black.DEFAULT_LINE_LENGTH, mode)

 
 

+    @event_loop(close=False)

     def test_check_diff_use_together(self) -> None:
         with cache_dir():
             # Files which will be reformatted.
     def test_check_diff_use_together(self) -> None:
         with cache_dir():
             # Files which will be reformatted.


@@ -611,7 +944,222 @@ class BlackTestCase(unittest.TestCase):
             result = CliRunner().invoke(
                 black.main, [str(src1), str(src2), "--diff", "--check"]
             )
             result = CliRunner().invoke(
                 black.main, [str(src1), str(src2), "--diff", "--check"]
             )

-            self.assertEqual(result.exit_code, 1)
+            self.assertEqual(result.exit_code, 1, result.output)
+
+    def test_no_files(self) -> None:
+        with cache_dir():
+            # Without an argument, black exits with error code 0.
+            result = CliRunner().invoke(black.main, [])
+            self.assertEqual(result.exit_code, 0)
+
+    def test_broken_symlink(self) -> None:
+        with cache_dir() as workspace:
+            symlink = workspace / "broken_link.py"
+            try:
+                symlink.symlink_to("nonexistent.py")
+            except OSError as e:
+                self.skipTest(f"Can't create symlinks: {e}")
+            result = CliRunner().invoke(black.main, [str(workspace.resolve())])
+            self.assertEqual(result.exit_code, 0)
+
+    def test_read_cache_line_lengths(self) -> None:
+        mode = black.FileMode.AUTO_DETECT
+        with cache_dir() as workspace:
+            path = (workspace / "file.py").resolve()
+            path.touch()
+            black.write_cache({}, [path], 1, mode)
+            one = black.read_cache(1, mode)
+            self.assertIn(path, one)
+            two = black.read_cache(2, mode)
+            self.assertNotIn(path, two)
+
+    def test_single_file_force_pyi(self) -> None:
+        reg_mode = black.FileMode.AUTO_DETECT
+        pyi_mode = black.FileMode.PYI
+        contents, expected = read_data("force_pyi")
+        with cache_dir() as workspace:
+            path = (workspace / "file.py").resolve()
+            with open(path, "w") as fh:
+                fh.write(contents)
+            result = CliRunner().invoke(black.main, [str(path), "--pyi"])
+            self.assertEqual(result.exit_code, 0)
+            with open(path, "r") as fh:
+                actual = fh.read()
+            # verify cache with --pyi is separate
+            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, pyi_mode)
+            self.assertIn(path, pyi_cache)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            self.assertNotIn(path, normal_cache)
+        self.assertEqual(actual, expected)
+
+    @event_loop(close=False)
+    def test_multi_file_force_pyi(self) -> None:
+        reg_mode = black.FileMode.AUTO_DETECT
+        pyi_mode = black.FileMode.PYI
+        contents, expected = read_data("force_pyi")
+        with cache_dir() as workspace:
+            paths = [
+                (workspace / "file1.py").resolve(),
+                (workspace / "file2.py").resolve(),
+            ]
+            for path in paths:
+                with open(path, "w") as fh:
+                    fh.write(contents)
+            result = CliRunner().invoke(black.main, [str(p) for p in paths] + ["--pyi"])
+            self.assertEqual(result.exit_code, 0)
+            for path in paths:
+                with open(path, "r") as fh:
+                    actual = fh.read()
+                self.assertEqual(actual, expected)
+            # verify cache with --pyi is separate
+            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, pyi_mode)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            for path in paths:
+                self.assertIn(path, pyi_cache)
+                self.assertNotIn(path, normal_cache)
+
+    def test_pipe_force_pyi(self) -> None:
+        source, expected = read_data("force_pyi")
+        result = CliRunner().invoke(black.main, ["-", "-q", "--pyi"], input=source)
+        self.assertEqual(result.exit_code, 0)
+        actual = result.output
+        self.assertFormatEqual(actual, expected)
+
+    def test_single_file_force_py36(self) -> None:
+        reg_mode = black.FileMode.AUTO_DETECT
+        py36_mode = black.FileMode.PYTHON36
+        source, expected = read_data("force_py36")
+        with cache_dir() as workspace:
+            path = (workspace / "file.py").resolve()
+            with open(path, "w") as fh:
+                fh.write(source)
+            result = CliRunner().invoke(black.main, [str(path), "--py36"])
+            self.assertEqual(result.exit_code, 0)
+            with open(path, "r") as fh:
+                actual = fh.read()
+            # verify cache with --py36 is separate
+            py36_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, py36_mode)
+            self.assertIn(path, py36_cache)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            self.assertNotIn(path, normal_cache)
+        self.assertEqual(actual, expected)
+
+    @event_loop(close=False)
+    def test_multi_file_force_py36(self) -> None:
+        reg_mode = black.FileMode.AUTO_DETECT
+        py36_mode = black.FileMode.PYTHON36
+        source, expected = read_data("force_py36")
+        with cache_dir() as workspace:
+            paths = [
+                (workspace / "file1.py").resolve(),
+                (workspace / "file2.py").resolve(),
+            ]
+            for path in paths:
+                with open(path, "w") as fh:
+                    fh.write(source)
+            result = CliRunner().invoke(
+                black.main, [str(p) for p in paths] + ["--py36"]
+            )
+            self.assertEqual(result.exit_code, 0)
+            for path in paths:
+                with open(path, "r") as fh:
+                    actual = fh.read()
+                self.assertEqual(actual, expected)
+            # verify cache with --py36 is separate
+            pyi_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, py36_mode)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH, reg_mode)
+            for path in paths:
+                self.assertIn(path, pyi_cache)
+                self.assertNotIn(path, normal_cache)
+
+    def test_pipe_force_py36(self) -> None:
+        source, expected = read_data("force_py36")
+        result = CliRunner().invoke(black.main, ["-", "-q", "--py36"], input=source)
+        self.assertEqual(result.exit_code, 0)
+        actual = result.output
+        self.assertFormatEqual(actual, expected)
+
+    def test_include_exclude(self) -> None:
+        path = THIS_DIR / "include_exclude_tests"
+        include = re.compile(r"\.pyi?$")
+        exclude = re.compile(r"/exclude/|/\.definitely_exclude/")
+        report = black.Report()
+        sources: List[Path] = []
+        expected = [
+            Path(THIS_DIR / "include_exclude_tests/b/dont_exclude/a.py"),
+            Path(THIS_DIR / "include_exclude_tests/b/dont_exclude/a.pyi"),
+        ]
+        this_abs = THIS_DIR.resolve()
+        sources.extend(
+            black.gen_python_files_in_dir(path, this_abs, include, exclude, report)
+        )
+        self.assertEqual(sorted(expected), sorted(sources))
+
+    def test_empty_include(self) -> None:
+        path = THIS_DIR / "include_exclude_tests"
+        report = black.Report()
+        empty = re.compile(r"")
+        sources: List[Path] = []
+        expected = [
+            Path(path / "b/exclude/a.pie"),
+            Path(path / "b/exclude/a.py"),
+            Path(path / "b/exclude/a.pyi"),
+            Path(path / "b/dont_exclude/a.pie"),
+            Path(path / "b/dont_exclude/a.py"),
+            Path(path / "b/dont_exclude/a.pyi"),
+            Path(path / "b/.definitely_exclude/a.pie"),
+            Path(path / "b/.definitely_exclude/a.py"),
+            Path(path / "b/.definitely_exclude/a.pyi"),
+        ]
+        this_abs = THIS_DIR.resolve()
+        sources.extend(
+            black.gen_python_files_in_dir(
+                path, this_abs, empty, re.compile(black.DEFAULT_EXCLUDES), report
+            )
+        )
+        self.assertEqual(sorted(expected), sorted(sources))
+
+    def test_empty_exclude(self) -> None:
+        path = THIS_DIR / "include_exclude_tests"
+        report = black.Report()
+        empty = re.compile(r"")
+        sources: List[Path] = []
+        expected = [
+            Path(path / "b/dont_exclude/a.py"),
+            Path(path / "b/dont_exclude/a.pyi"),
+            Path(path / "b/exclude/a.py"),
+            Path(path / "b/exclude/a.pyi"),
+            Path(path / "b/.definitely_exclude/a.py"),
+            Path(path / "b/.definitely_exclude/a.pyi"),
+        ]
+        this_abs = THIS_DIR.resolve()
+        sources.extend(
+            black.gen_python_files_in_dir(
+                path, this_abs, re.compile(black.DEFAULT_INCLUDES), empty, report
+            )
+        )
+        self.assertEqual(sorted(expected), sorted(sources))
+
+    def test_invalid_include_exclude(self) -> None:
+        for option in ["--include", "--exclude"]:
+            result = CliRunner().invoke(black.main, ["-", option, "**()(!!*)"])
+            self.assertEqual(result.exit_code, 2)
+
+    def test_preserves_line_endings(self) -> None:
+        with TemporaryDirectory() as workspace:
+            test_file = Path(workspace) / "test.py"
+            for nl in ["\n", "\r\n"]:
+                contents = nl.join(["def f(  ):", "    pass"])
+                test_file.write_bytes(contents.encode())
+                ff(test_file, write_back=black.WriteBack.YES)
+                updated_contents: bytes = test_file.read_bytes()
+                self.assertIn(nl.encode(), updated_contents)  # type: ignore
+                if nl == "\n":
+                    self.assertNotIn(b"\r\n", updated_contents)  # type: ignore
+
+    def test_assert_equivalent_different_asts(self) -> None:
+        with self.assertRaises(AssertionError):
+            black.assert_equivalent("{}", "None")

 
 
 if __name__ == "__main__":
 
 
 if __name__ == "__main__":