How to use black - 10 common examples

def test_cantfit(self) -> None:
        source, expected = read_data("cantfit")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def assertFormatEqual(self, expected: str, actual: str) -> None:
        if actual != expected and not os.environ.get("SKIP_AST_PRINT"):
            bdv: black.DebugVisitor[Any]
            black.out("Expected tree:", fg="green")
            try:
                exp_node = black.lib2to3_parse(expected)
                bdv = black.DebugVisitor()
                list(bdv.visit(exp_node))
            except Exception as ve:
                black.err(str(ve))
            black.out("Actual tree:", fg="red")
            try:
                exp_node = black.lib2to3_parse(actual)
                bdv = black.DebugVisitor()
                list(bdv.visit(exp_node))
            except Exception as ve:
                black.err(str(ve))
        self.assertEqual(expected, actual)

def test_fstring(self) -> None:
        source, expected = read_data("fstring")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def test_composition(self) -> None:
        source, expected = read_data("composition")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def test_import_spacing(self) -> None:
        source, expected = read_data("import_spacing")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def checkSourceFile(self, name: str) -> None:
        path = THIS_DIR.parent / name
        source, expected = read_data(str(path), data=False)
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())
        self.assertFalse(ff(path))

def test_async_as_identifier(self) -> None:
        source_path = (THIS_DIR / "data" / "async_as_identifier.py").resolve()
        source, expected = read_data("async_as_identifier")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        major, minor = sys.version_info[:2]
        if major < 3 or (major <= 3 and minor < 7):
            black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())
        # ensure black can parse this when the target is 3.6
        self.invokeBlack([str(source_path), "--target-version", "py36"])
        # but not on 3.7, because async/await is no longer an identifier
        self.invokeBlack([str(source_path), "--target-version", "py37"], exit_code=123)

def test_comments4(self) -> None:
        source, expected = read_data("comments4")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def test_comment_after_escaped_newline(self) -> None:
        source, expected = read_data("comment_after_escaped_newline")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())

def test_tuple_assign(self) -> None:
        source, expected = read_data("tupleassign")
        actual = fs(source)
        self.assertFormatEqual(expected, actual)
        black.assert_equivalent(source, actual)
        black.assert_stable(source, actual, black.FileMode())