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Add instructions for running Black on save in Vim (#255)
[etc/vim.git] / tests / test_black.py
index a4d23823c9d2164cfb0176d8544ca01e6d23fc47..a7d04cc548f310583793b5656913dd71604ac332 100644 (file)
@@ -1,14 +1,19 @@
 #!/usr/bin/env python3
 #!/usr/bin/env python3
+import asyncio
+from concurrent.futures import ThreadPoolExecutor
+from contextlib import contextmanager
 from functools import partial
 from io import StringIO
 import os
 from pathlib import Path
 import sys
 from functools import partial
 from io import StringIO
 import os
 from pathlib import Path
 import sys
-from typing import Any, List, Tuple
+from tempfile import TemporaryDirectory
+from typing import Any, List, Tuple, Iterator
 import unittest
 from unittest.mock import patch
 
 from click import unstyle
 import unittest
 from unittest.mock import patch
 
 from click import unstyle
+from click.testing import CliRunner
 
 import black
 
 
 import black
 
@@ -26,7 +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] = []
@@ -46,6 +51,31 @@ def read_data(name: str) -> Tuple[str, str]:
     return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
 
 
     return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
 
 
+@contextmanager
+def cache_dir(exists: bool = True) -> Iterator[Path]:
+    with TemporaryDirectory() as workspace:
+        cache_dir = Path(workspace)
+        if not exists:
+            cache_dir = cache_dir / "new"
+        with patch("black.CACHE_DIR", cache_dir):
+            yield cache_dir
+
+
+@contextmanager
+def event_loop(close: bool) -> Iterator[None]:
+    policy = asyncio.get_event_loop_policy()
+    old_loop = policy.get_event_loop()
+    loop = policy.new_event_loop()
+    asyncio.set_event_loop(loop)
+    try:
+        yield
+
+    finally:
+        policy.set_event_loop(old_loop)
+        if close:
+            loop.close()
+
+
 class BlackTestCase(unittest.TestCase):
     maxDiff = None
 
 class BlackTestCase(unittest.TestCase):
     maxDiff = None
 
@@ -137,6 +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")
@@ -169,7 +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)
@@ -199,6 +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")
@@ -231,6 +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")
@@ -263,6 +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")
@@ -271,6 +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")
@@ -279,6 +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 = []
@@ -291,67 +375,76 @@ class BlackTestCase(unittest.TestCase):
             err_lines.append(msg)
 
         with patch("black.out", out), patch("black.err", err):
             err_lines.append(msg)
 
         with patch("black.out", out), patch("black.err", err):
-            report.done(Path("f1"), changed=False)
+            report.done(Path("f1"), black.Changed.NO)
             self.assertEqual(len(out_lines), 1)
             self.assertEqual(len(err_lines), 0)
             self.assertEqual(out_lines[-1], "f1 already well formatted, good job.")
             self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
             self.assertEqual(report.return_code, 0)
             self.assertEqual(len(out_lines), 1)
             self.assertEqual(len(err_lines), 0)
             self.assertEqual(out_lines[-1], "f1 already well formatted, good job.")
             self.assertEqual(unstyle(str(report)), "1 file left unchanged.")
             self.assertEqual(report.return_code, 0)
-            report.done(Path("f2"), changed=True)
+            report.done(Path("f2"), black.Changed.YES)
             self.assertEqual(len(out_lines), 2)
             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."
             )
             self.assertEqual(len(out_lines), 2)
             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), 3)
+            self.assertEqual(len(err_lines), 0)
+            self.assertEqual(
+                out_lines[-1], "f3 wasn't modified on disk since last run."
+            )
+            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(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), 2)
+            self.assertEqual(len(out_lines), 3)
             self.assertEqual(len(err_lines), 1)
             self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
             self.assertEqual(
                 unstyle(str(report)),
             self.assertEqual(len(err_lines), 1)
             self.assertEqual(err_lines[-1], "error: cannot format e1: boom")
             self.assertEqual(
                 unstyle(str(report)),
-                "1 file reformatted, 1 file left unchanged, "
+                "1 file reformatted, 2 files left unchanged, "
                 "1 file failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
                 "1 file failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
-            report.done(Path("f3"), changed=True)
-            self.assertEqual(len(out_lines), 3)
+            report.done(Path("f3"), black.Changed.YES)
+            self.assertEqual(len(out_lines), 4)
             self.assertEqual(len(err_lines), 1)
             self.assertEqual(out_lines[-1], "reformatted f3")
             self.assertEqual(
                 unstyle(str(report)),
             self.assertEqual(len(err_lines), 1)
             self.assertEqual(out_lines[-1], "reformatted f3")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 1 file left unchanged, "
+                "2 files reformatted, 2 files left unchanged, "
                 "1 file failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.failed(Path("e2"), "boom")
                 "1 file failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.failed(Path("e2"), "boom")
-            self.assertEqual(len(out_lines), 3)
+            self.assertEqual(len(out_lines), 4)
             self.assertEqual(len(err_lines), 2)
             self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
             self.assertEqual(
                 unstyle(str(report)),
             self.assertEqual(len(err_lines), 2)
             self.assertEqual(err_lines[-1], "error: cannot format e2: boom")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 1 file left unchanged, "
+                "2 files reformatted, 2 files left unchanged, "
                 "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"), changed=False)
-            self.assertEqual(len(out_lines), 4)
+            report.done(Path("f4"), black.Changed.NO)
+            self.assertEqual(len(out_lines), 5)
             self.assertEqual(len(err_lines), 2)
             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
             self.assertEqual(
                 unstyle(str(report)),
             self.assertEqual(len(err_lines), 2)
             self.assertEqual(out_lines[-1], "f4 already well formatted, good job.")
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files reformatted, 2 files left unchanged, "
+                "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 failed to reformat.",
             )
             self.assertEqual(report.return_code, 123)
             report.check = True
             self.assertEqual(
                 unstyle(str(report)),
-                "2 files would be reformatted, 2 files would be left unchanged, "
+                "2 files would be reformatted, 3 files would be left unchanged, "
                 "2 files would fail to reformat.",
             )
 
                 "2 files would fail to reformat.",
             )
 
@@ -373,6 +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")
@@ -442,6 +557,267 @@ class BlackTestCase(unittest.TestCase):
         self.assertTrue("Actual tree:" in out_str)
         self.assertEqual("".join(err_lines), "")
 
         self.assertTrue("Actual tree:" in out_str)
         self.assertEqual("".join(err_lines), "")
 
+    def test_cache_broken_file(self) -> None:
+        with cache_dir() as workspace:
+            cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH)
+            with cache_file.open("w") as fobj:
+                fobj.write("this is not a pickle")
+            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)
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            self.assertIn(src, cache)
+
+    def test_cache_single_file_already_cached(self) -> None:
+        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.DEFAULT_LINE_LENGTH)
+            result = CliRunner().invoke(black.main, [str(src)])
+            self.assertEqual(result.exit_code, 0)
+            with src.open("r") as fobj:
+                self.assertEqual(fobj.read(), "print('hello')")
+
+    @event_loop(close=False)
+    def test_cache_multiple_files(self) -> None:
+        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')")
+            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')
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            self.assertIn(one, cache)
+            self.assertIn(two, cache)
+
+    def test_no_cache_when_writeback_diff(self) -> None:
+        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)
+            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)
+            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():
+            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()
+            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))
+
+    def test_filter_cached(self) -> None:
+        with TemporaryDirectory() as workspace:
+            path = Path(workspace)
+            uncached = (path / "uncached").resolve()
+            cached = (path / "cached").resolve()
+            cached_but_changed = (path / "changed").resolve()
+            uncached.touch()
+            cached.touch()
+            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]
+            )
+            self.assertEqual(todo, [uncached, cached_but_changed])
+            self.assertEqual(done, [cached])
+
+    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.DEFAULT_LINE_LENGTH)
+            self.assertTrue(workspace.exists())
+
+    @event_loop(close=False)
+    def test_failed_formatting_does_not_get_cached(self) -> None:
+        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")
+            clean = (workspace / "clean.py").resolve()
+            with clean.open("w") as fobj:
+                fobj.write('print("hello")\n')
+            result = CliRunner().invoke(black.main, [str(workspace)])
+            self.assertEqual(result.exit_code, 123)
+            cache = black.read_cache(black.DEFAULT_LINE_LENGTH)
+            self.assertNotIn(failing, cache)
+            self.assertIn(clean, cache)
+
+    def test_write_cache_write_fail(self) -> None:
+        with cache_dir(), patch.object(Path, "open") as mock:
+            mock.side_effect = OSError
+            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__":
     unittest.main()
 
 if __name__ == "__main__":
     unittest.main()