Update changelog for PR 249.

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

diff --git a/tests/test_black.py b/tests/test_black.py
index a64033cbc66fe7b6b45dfc345f4a18ec4f37f225..a7d04cc548f310583793b5656913dd71604ac332 100644 (file)
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -1,5 +1,6 @@
 #!/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 io import StringIO
 from contextlib import contextmanager
 from functools import partial
 from io import StringIO


@@ -30,7 +31,7 @@ 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 +57,7 @@ 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
 
 


@@ -105,7 +105,7 @@ 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)

-        self.assertIs(ff(THIS_FILE), black.Changed.NO)
+        self.assertFalse(ff(THIS_FILE))

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


@@ -114,7 +114,7 @@ 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)

-        self.assertIs(ff(THIS_DIR / ".." / "black.py"), black.Changed.NO)
+        self.assertFalse(ff(THIS_DIR / ".." / "black.py"))

 
     def test_piping(self) -> None:
         source, expected = read_data("../black")
 
     def test_piping(self) -> None:
         source, expected = read_data("../black")


@@ -157,7 +157,7 @@ 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)

-        self.assertIs(ff(THIS_DIR / ".." / "setup.py"), black.Changed.NO)
+        self.assertFalse(ff(THIS_DIR / ".." / "setup.py"))

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


@@ -167,6 +167,14 @@ 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")


@@ -199,7 +207,7 @@ class BlackTestCase(unittest.TestCase):
             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.DIFF))
             sys.stdout.seek(0)
             actual = sys.stdout.read()
             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>")
+            actual = actual.replace(str(tmp_file), "<stdin>")

         finally:
             sys.stdout = hold_stdout
             os.unlink(tmp_file)
         finally:
             sys.stdout = hold_stdout
             os.unlink(tmp_file)


@@ -229,6 +237,14 @@ 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_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:
         source, expected = read_data("comments")
     @patch("black.dump_to_file", dump_to_stderr)
     def test_comments(self) -> None:
         source, expected = read_data("comments")


@@ -261,6 +277,14 @@ 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 +317,14 @@ 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 +333,20 @@ 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:
+        source, expected = read_data("stub.pyi")
+        actual = fs(source, is_pyi=True)
+        self.assertFormatEqual(expected, actual)
+        black.assert_stable(source, actual, line_length=ll, is_pyi=True)
+

     @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")


@@ -309,6 +355,14 @@ 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_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)
+

     def test_report(self) -> None:
         report = black.Report()
         out_lines = []
     def test_report(self) -> None:
         report = black.Report()
         out_lines = []


@@ -412,6 +466,28 @@ 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")


@@ -483,15 +559,16 @@ class BlackTestCase(unittest.TestCase):
 
     def test_cache_broken_file(self) -> None:
         with cache_dir() as workspace:
 
     def test_cache_broken_file(self) -> None:
         with cache_dir() as workspace:

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

             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)

             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:


@@ -499,7 +576,7 @@ class BlackTestCase(unittest.TestCase):
             src = (workspace / "test.py").resolve()
             with src.open("w") as fobj:
                 fobj.write("print('hello')")
             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)

             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:


@@ -507,21 +584,23 @@ 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:
+        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)

             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)

             self.assertIn(one, cache)
             self.assertIn(two, cache)
 
             self.assertIn(one, cache)
             self.assertIn(two, cache)
 


@@ -532,24 +611,26 @@ class BlackTestCase(unittest.TestCase):
                 fobj.write("print('hello')")
             result = CliRunner().invoke(black.main, [str(src), "--diff"])
             self.assertEqual(result.exit_code, 0)
                 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)
+            self.assertFalse(cache_file.exists())

 
     def test_no_cache_when_stdin(self) -> None:
         with cache_dir():
             result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
             self.assertEqual(result.exit_code, 0)
 
     def test_no_cache_when_stdin(self) -> None:
         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)
+            self.assertFalse(cache_file.exists())

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

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

 
     def test_write_cache_read_cache(self) -> None:
         with cache_dir() as workspace:
             src = (workspace / "test.py").resolve()
             src.touch()
 
     def test_write_cache_read_cache(self) -> None:
         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)
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH)

             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))
 


@@ -572,12 +653,14 @@ class BlackTestCase(unittest.TestCase):
     def test_write_cache_creates_directory_if_needed(self) -> None:
         with cache_dir(exists=False) as workspace:
             self.assertFalse(workspace.exists())
     def test_write_cache_creates_directory_if_needed(self) -> None:
         with cache_dir(exists=False) as workspace:
             self.assertFalse(workspace.exists())

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

             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:
+        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")


@@ -586,14 +669,154 @@ 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)

             self.assertNotIn(failing, cache)
             self.assertIn(clean, cache)
 
             self.assertNotIn(failing, cache)
             self.assertIn(clean, cache)
 

-    def test_write_cache_write_fail(self):
+    def test_write_cache_write_fail(self) -> None:

         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)
+
+    @event_loop(close=False)
+    def test_check_diff_use_together(self) -> None:
+        with cache_dir():
+            # Files which will be reformatted.
+            src1 = (THIS_DIR / "string_quotes.py").resolve()
+            result = CliRunner().invoke(black.main, [str(src1), "--diff", "--check"])
+            self.assertEqual(result.exit_code, 1)
+
+            # Files which will not be reformatted.
+            src2 = (THIS_DIR / "composition.py").resolve()
+            result = CliRunner().invoke(black.main, [str(src2), "--diff", "--check"])
+            self.assertEqual(result.exit_code, 0)
+
+            # Multi file command.
+            result = CliRunner().invoke(
+                black.main, [str(src1), str(src2), "--diff", "--check"]
+            )
+            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"
+            symlink.symlink_to("nonexistent.py")
+            result = CliRunner().invoke(black.main, [str(workspace.resolve())])
+            self.assertEqual(result.exit_code, 0)
+
+    def test_read_cache_line_lengths(self) -> None:
+        with cache_dir() as workspace:
+            path = (workspace / "file.py").resolve()
+            path.touch()
+            black.write_cache({}, [path], 1)
+            one = black.read_cache(1)
+            self.assertIn(path, one)
+            two = black.read_cache(2)
+            self.assertNotIn(path, two)
+
+    def test_single_file_force_pyi(self) -> None:
+        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=True)
+            self.assertIn(path, pyi_cache)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            self.assertNotIn(path, normal_cache)
+        self.assertEqual(actual, expected)
+
+    @event_loop(close=False)
+    def test_multi_file_force_pyi(self) -> None:
+        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=True)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            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:
+        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=True)
+            self.assertIn(path, py36_cache)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            self.assertNotIn(path, normal_cache)
+        self.assertEqual(actual, expected)
+
+    @event_loop(close=False)
+    def test_multi_file_force_py36(self) -> None:
+        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=True)
+            normal_cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            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)

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