Add support for special comments in multiline functions (#642)

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

diff --git a/tests/test_black.py b/tests/test_black.py
index 191f4b8cd40638bedcadcb4b26a6769403725f6c..078e8d8ce30c98f908a0134e89ea765ea2236b32 100644 (file)
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -1,15 +1,25 @@
 #!/usr/bin/env python3
 import asyncio
 from concurrent.futures import ThreadPoolExecutor
 #!/usr/bin/env python3
 import asyncio
 from concurrent.futures import ThreadPoolExecutor

-from contextlib import contextmanager
-from functools import partial
+from contextlib import contextmanager, redirect_stderr
+from functools import partial, wraps

 from io import BytesIO, TextIOWrapper
 import os
 from pathlib import Path
 import re
 import sys
 from tempfile import TemporaryDirectory
 from io import BytesIO, TextIOWrapper
 import os
 from pathlib import Path
 import re
 import sys
 from tempfile import TemporaryDirectory

-from typing import Any, BinaryIO, Generator, List, Tuple, Iterator
+from typing import (
+    Any,
+    BinaryIO,
+    Callable,
+    Coroutine,
+    Generator,
+    List,
+    Tuple,
+    Iterator,
+    TypeVar,
+)

 import unittest
 from unittest.mock import patch, MagicMock
 
 import unittest
 from unittest.mock import patch, MagicMock
 


@@ -18,6 +28,14 @@ from click.testing import CliRunner
 
 import black
 
 
 import black
 

+try:
+    import blackd
+    from aiohttp.test_utils import TestClient, TestServer
+except ImportError:
+    has_blackd_deps = False
+else:
+    has_blackd_deps = True
+

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


@@ -25,6 +43,8 @@ fs = partial(black.format_str, line_length=ll)
 THIS_FILE = Path(__file__)
 THIS_DIR = THIS_FILE.parent
 EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
 THIS_FILE = Path(__file__)
 THIS_DIR = THIS_FILE.parent
 EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"

+T = TypeVar("T")
+R = TypeVar("R")

 
 
 def dump_to_stderr(*output: str) -> str:
 
 
 def dump_to_stderr(*output: str) -> str:


@@ -79,13 +99,25 @@ def event_loop(close: bool) -> Iterator[None]:
             loop.close()
 
 
             loop.close()
 
 

+def async_test(f: Callable[..., Coroutine[Any, None, R]]) -> Callable[..., None]:
+    @event_loop(close=True)
+    @wraps(f)
+    def wrapper(*args: Any, **kwargs: Any) -> None:
+        asyncio.get_event_loop().run_until_complete(f(*args, **kwargs))
+
+    return wrapper
+
+

 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"""
 
 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
+    def __init__(self) -> None:
+        self.stderrbuf = BytesIO()
+        self.stdoutbuf = BytesIO()
+        self.stdout_bytes = b""
+        self.stderr_bytes = b""

         super().__init__()
 
     @contextmanager
         super().__init__()
 
     @contextmanager


@@ -96,6 +128,8 @@ class BlackRunner(CliRunner):
                 sys.stderr = TextIOWrapper(self.stderrbuf, encoding=self.charset)
                 yield output
             finally:
                 sys.stderr = TextIOWrapper(self.stderrbuf, encoding=self.charset)
                 yield output
             finally:

+                self.stdout_bytes = sys.stdout.buffer.getvalue()  # type: ignore
+                self.stderr_bytes = sys.stderr.buffer.getvalue()  # type: ignore

                 sys.stderr = hold_stderr
 
 
                 sys.stderr = hold_stderr
 
 


@@ -160,9 +194,10 @@ class BlackTestCase(unittest.TestCase):
 
     def test_piping(self) -> None:
         source, expected = read_data("../black", data=False)
 
     def test_piping(self) -> None:
         source, expected = read_data("../black", data=False)

-        stderrbuf = BytesIO()
-        result = BlackRunner(stderrbuf).invoke(
-            black.main, ["-", "--fast", f"--line-length={ll}"], input=source
+        result = BlackRunner().invoke(
+            black.main,
+            ["-", "--fast", f"--line-length={ll}"],
+            input=BytesIO(source.encode("utf8")),

         )
         self.assertEqual(result.exit_code, 0)
         self.assertFormatEqual(expected, result.output)
         )
         self.assertEqual(result.exit_code, 0)
         self.assertFormatEqual(expected, result.output)


@@ -177,9 +212,10 @@ class BlackTestCase(unittest.TestCase):
         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")
         config = THIS_DIR / "data" / "empty_pyproject.toml"
         source, _ = read_data("expression.py")
         expected, _ = read_data("expression.diff")
         config = THIS_DIR / "data" / "empty_pyproject.toml"

-        stderrbuf = BytesIO()

         args = ["-", "--fast", f"--line-length={ll}", "--diff", f"--config={config}"]
         args = ["-", "--fast", f"--line-length={ll}", "--diff", f"--config={config}"]

-        result = BlackRunner(stderrbuf).invoke(black.main, args, input=source)
+        result = BlackRunner().invoke(
+            black.main, args, input=BytesIO(source.encode("utf8"))
+        )

         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(result.exit_code, 0)
         actual = diff_header.sub("[Deterministic header]", result.output)
         actual = actual.rstrip() + "\n"  # the diff output has a trailing space


@@ -240,11 +276,8 @@ class BlackTestCase(unittest.TestCase):
             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"
         )
             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:

-            result = BlackRunner(stderrbuf).invoke(
-                black.main, ["--diff", str(tmp_file)]
-            )
+            result = BlackRunner().invoke(black.main, ["--diff", str(tmp_file)])

             self.assertEqual(result.exit_code, 0)
         finally:
             os.unlink(tmp_file)
             self.assertEqual(result.exit_code, 0)
         finally:
             os.unlink(tmp_file)


@@ -329,6 +362,14 @@ 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_comments6(self) -> None:
+        source, expected = read_data("comments6")
+        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")


@@ -369,6 +410,32 @@ 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_numeric_literals(self) -> None:
+        source, expected = read_data("numeric_literals")
+        actual = fs(source, mode=black.FileMode.PYTHON36)
+        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_numeric_literals_ignoring_underscores(self) -> None:
+        source, expected = read_data("numeric_literals_skip_underscores")
+        mode = (
+            black.FileMode.PYTHON36 | black.FileMode.NO_NUMERIC_UNDERSCORE_NORMALIZATION
+        )
+        actual = fs(source, mode=mode)
+        self.assertFormatEqual(expected, actual)
+        black.assert_equivalent(source, actual)
+        black.assert_stable(source, actual, line_length=ll, mode=mode)
+
+    @patch("black.dump_to_file", dump_to_stderr)
+    def test_numeric_literals_py2(self) -> None:
+        source, expected = read_data("numeric_literals_py2")
+        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_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")


@@ -392,6 +459,16 @@ class BlackTestCase(unittest.TestCase):
         self.assertFormatEqual(expected, actual)
         black.assert_stable(source, actual, line_length=ll, 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_python37(self) -> None:
+        source, expected = read_data("python37")
+        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, line_length=ll)
+

     @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")


@@ -424,6 +501,14 @@ 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_bracket_match(self) -> None:
+        source, expected = read_data("bracketmatch")
+        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 = []
     def test_report_verbose(self) -> None:
         report = black.Report(verbose=True)
         out_lines = []


@@ -703,6 +788,10 @@ class BlackTestCase(unittest.TestCase):
         self.assertTrue(black.is_python36(node))
         node = black.lib2to3_parse("def f(*, arg): f'string'\n")
         self.assertTrue(black.is_python36(node))
         self.assertTrue(black.is_python36(node))
         node = black.lib2to3_parse("def f(*, arg): f'string'\n")
         self.assertTrue(black.is_python36(node))

+        node = black.lib2to3_parse("123_456\n")
+        self.assertTrue(black.is_python36(node))
+        node = black.lib2to3_parse("123456\n")
+        self.assertFalse(black.is_python36(node))

         source, expected = read_data("function")
         node = black.lib2to3_parse(source)
         self.assertTrue(black.is_python36(node))
         source, expected = read_data("function")
         node = black.lib2to3_parse(source)
         self.assertTrue(black.is_python36(node))


@@ -735,6 +824,14 @@ class BlackTestCase(unittest.TestCase):
         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))
         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))

+        node = black.lib2to3_parse(
+            "from __future__ import unicode_literals as _unicode_literals"
+        )
+        self.assertEqual({"unicode_literals"}, black.get_future_imports(node))
+        node = black.lib2to3_parse(
+            "from __future__ import unicode_literals as _lol, print"
+        )
+        self.assertEqual({"unicode_literals", "print"}, black.get_future_imports(node))

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


@@ -775,7 +872,7 @@ class BlackTestCase(unittest.TestCase):
         actual = black.format_file_contents(different, line_length=ll, fast=False)
         self.assertEqual(expected, actual)
         invalid = "return if you can"
         actual = black.format_file_contents(different, line_length=ll, fast=False)
         self.assertEqual(expected, actual)
         invalid = "return if you can"

-        with self.assertRaises(ValueError) as e:
+        with self.assertRaises(black.InvalidInput) as e:

             black.format_file_contents(invalid, line_length=ll, fast=False)
         self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
 
             black.format_file_contents(invalid, line_length=ll, fast=False)
         self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
 


@@ -869,7 +966,9 @@ class BlackTestCase(unittest.TestCase):
     def test_no_cache_when_stdin(self) -> None:
         mode = black.FileMode.AUTO_DETECT
         with cache_dir():
     def test_no_cache_when_stdin(self) -> None:
         mode = black.FileMode.AUTO_DETECT
         with cache_dir():

-            result = CliRunner().invoke(black.main, ["-"], input="print('hello')")
+            result = CliRunner().invoke(
+                black.main, ["-"], input=BytesIO(b"print('hello')")
+            )

             self.assertEqual(result.exit_code, 0)
             cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
             self.assertFalse(cache_file.exists())
             self.assertEqual(result.exit_code, 0)
             cache_file = black.get_cache_file(black.DEFAULT_LINE_LENGTH, mode)
             self.assertFalse(cache_file.exists())


@@ -943,12 +1042,10 @@ class BlackTestCase(unittest.TestCase):
             src1 = (THIS_DIR / "data" / "string_quotes.py").resolve()
             result = CliRunner().invoke(black.main, [str(src1), "--diff", "--check"])
             self.assertEqual(result.exit_code, 1, result.output)
             src1 = (THIS_DIR / "data" / "string_quotes.py").resolve()
             result = CliRunner().invoke(black.main, [str(src1), "--diff", "--check"])
             self.assertEqual(result.exit_code, 1, result.output)

-

             # Files which will not be reformatted.
             src2 = (THIS_DIR / "data" / "composition.py").resolve()
             result = CliRunner().invoke(black.main, [str(src2), "--diff", "--check"])
             self.assertEqual(result.exit_code, 0, result.output)
             # Files which will not be reformatted.
             src2 = (THIS_DIR / "data" / "composition.py").resolve()
             result = CliRunner().invoke(black.main, [str(src2), "--diff", "--check"])
             self.assertEqual(result.exit_code, 0, result.output)

-

             # Multi file command.
             result = CliRunner().invoke(
                 black.main, [str(src1), str(src2), "--diff", "--check"]
             # Multi file command.
             result = CliRunner().invoke(
                 black.main, [str(src1), str(src2), "--diff", "--check"]


@@ -1029,7 +1126,9 @@ class BlackTestCase(unittest.TestCase):
 
     def test_pipe_force_pyi(self) -> None:
         source, expected = read_data("force_pyi")
 
     def test_pipe_force_pyi(self) -> None:
         source, expected = read_data("force_pyi")

-        result = CliRunner().invoke(black.main, ["-", "-q", "--pyi"], input=source)
+        result = CliRunner().invoke(
+            black.main, ["-", "-q", "--pyi"], input=BytesIO(source.encode("utf8"))
+        )

         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)
         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)


@@ -1083,7 +1182,9 @@ class BlackTestCase(unittest.TestCase):
 
     def test_pipe_force_py36(self) -> None:
         source, expected = read_data("force_py36")
 
     def test_pipe_force_py36(self) -> None:
         source, expected = read_data("force_py36")

-        result = CliRunner().invoke(black.main, ["-", "-q", "--py36"], input=source)
+        result = CliRunner().invoke(
+            black.main, ["-", "-q", "--py36"], input=BytesIO(source.encode("utf8"))
+        )

         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)
         self.assertEqual(result.exit_code, 0)
         actual = result.output
         self.assertFormatEqual(actual, expected)


@@ -1162,50 +1263,51 @@ class BlackTestCase(unittest.TestCase):
                 test_file.write_bytes(contents.encode())
                 ff(test_file, write_back=black.WriteBack.YES)
                 updated_contents: bytes = test_file.read_bytes()
                 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
+                self.assertIn(nl.encode(), updated_contents)

                 if nl == "\n":
                 if nl == "\n":

-                    self.assertNotIn(b"\r\n", updated_contents)  # type: ignore
+                    self.assertNotIn(b"\r\n", updated_contents)
+
+    def test_preserves_line_endings_via_stdin(self) -> None:
+        for nl in ["\n", "\r\n"]:
+            contents = nl.join(["def f(  ):", "    pass"])
+            runner = BlackRunner()
+            result = runner.invoke(
+                black.main, ["-", "--fast"], input=BytesIO(contents.encode("utf8"))
+            )
+            self.assertEqual(result.exit_code, 0)
+            output = runner.stdout_bytes
+            self.assertIn(nl.encode("utf8"), output)
+            if nl == "\n":
+                self.assertNotIn(b"\r\n", output)

 
     def test_assert_equivalent_different_asts(self) -> None:
         with self.assertRaises(AssertionError):
             black.assert_equivalent("{}", "None")
 
     def test_symlink_out_of_root_directory(self) -> None:
 
     def test_assert_equivalent_different_asts(self) -> None:
         with self.assertRaises(AssertionError):
             black.assert_equivalent("{}", "None")
 
     def test_symlink_out_of_root_directory(self) -> None:

-        # prepare argumens

         path = MagicMock()
         root = THIS_DIR
         child = MagicMock()
         include = re.compile(black.DEFAULT_INCLUDES)
         exclude = re.compile(black.DEFAULT_EXCLUDES)
         report = black.Report()
         path = MagicMock()
         root = THIS_DIR
         child = MagicMock()
         include = re.compile(black.DEFAULT_INCLUDES)
         exclude = re.compile(black.DEFAULT_EXCLUDES)
         report = black.Report()

-
-        # set the behavior of mock arguments
-        # child should behave like a symlink which resolved path is clearly
-        # outside of the root directory
+        # `child` should behave like a symlink which resolved path is clearly
+        # outside of the `root` directory.

         path.iterdir.return_value = [child]
         child.resolve.return_value = Path("/a/b/c")
         child.is_symlink.return_value = True
         path.iterdir.return_value = [child]
         child.resolve.return_value = Path("/a/b/c")
         child.is_symlink.return_value = True

-
-        # call the method
-        # it should not raise any error
-        list(black.gen_python_files_in_dir(path, root, include, exclude, report))
-
-        # check the call of the methods of the mock objects
+        try:
+            list(black.gen_python_files_in_dir(path, root, include, exclude, report))
+        except ValueError as ve:
+            self.fail(f"`get_python_files_in_dir()` failed: {ve}")

         path.iterdir.assert_called_once()
         child.resolve.assert_called_once()
         child.is_symlink.assert_called_once()
         path.iterdir.assert_called_once()
         child.resolve.assert_called_once()
         child.is_symlink.assert_called_once()

-
-        # set the behavior of mock arguments
-        # child should behave like a strange file which resolved path is clearly
-        # outside of the root directory
+        # `child` should behave like a strange file which resolved path is clearly
+        # outside of the `root` directory.

         child.is_symlink.return_value = False
         child.is_symlink.return_value = False

-
-        # call the method
-        # it should raise a ValueError

         with self.assertRaises(ValueError):
             list(black.gen_python_files_in_dir(path, root, include, exclude, report))
         with self.assertRaises(ValueError):
             list(black.gen_python_files_in_dir(path, root, include, exclude, report))

-
-        # check the call of the methods of the mock objects

         path.iterdir.assert_called()
         self.assertEqual(path.iterdir.call_count, 2)
         child.resolve.assert_called()
         path.iterdir.assert_called()
         self.assertEqual(path.iterdir.call_count, 2)
         child.resolve.assert_called()


@@ -1235,6 +1337,172 @@ class BlackTestCase(unittest.TestCase):
             except RuntimeError as re:
                 self.fail(f"`patch_click()` failed, exception still raised: {re}")
 
             except RuntimeError as re:
                 self.fail(f"`patch_click()` failed, exception still raised: {re}")
 

+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_request_needs_formatting(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post("/", data=b"print('hello world')")
+            self.assertEqual(response.status, 200)
+            self.assertEqual(response.charset, "utf8")
+            self.assertEqual(await response.read(), b'print("hello world")\n')
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_request_no_change(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post("/", data=b'print("hello world")\n')
+            self.assertEqual(response.status, 204)
+            self.assertEqual(await response.read(), b"")
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_request_syntax_error(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post("/", data=b"what even ( is")
+            self.assertEqual(response.status, 400)
+            content = await response.text()
+            self.assertTrue(
+                content.startswith("Cannot parse"),
+                msg=f"Expected error to start with 'Cannot parse', got {repr(content)}",
+            )
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_unsupported_version(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/", data=b"what", headers={blackd.VERSION_HEADER: "2"}
+            )
+            self.assertEqual(response.status, 501)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_supported_version(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/", data=b"what", headers={blackd.VERSION_HEADER: "1"}
+            )
+            self.assertEqual(response.status, 200)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_invalid_python_variant(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/", data=b"what", headers={blackd.PYTHON_VARIANT_HEADER: "lol"}
+            )
+            self.assertEqual(response.status, 400)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_pyi(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            source, expected = read_data("stub.pyi")
+            response = await client.post(
+                "/", data=source, headers={blackd.PYTHON_VARIANT_HEADER: "pyi"}
+            )
+            self.assertEqual(response.status, 200)
+            self.assertEqual(await response.text(), expected)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_py36(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/",
+                data=(
+                    "def f(\n"
+                    "    and_has_a_bunch_of,\n"
+                    "    very_long_arguments_too,\n"
+                    "    and_lots_of_them_as_well_lol,\n"
+                    "    **and_very_long_keyword_arguments\n"
+                    "):\n"
+                    "    pass\n"
+                ),
+                headers={blackd.PYTHON_VARIANT_HEADER: "3.6"},
+            )
+            self.assertEqual(response.status, 200)
+            response = await client.post(
+                "/",
+                data=(
+                    "def f(\n"
+                    "    and_has_a_bunch_of,\n"
+                    "    very_long_arguments_too,\n"
+                    "    and_lots_of_them_as_well_lol,\n"
+                    "    **and_very_long_keyword_arguments\n"
+                    "):\n"
+                    "    pass\n"
+                ),
+                headers={blackd.PYTHON_VARIANT_HEADER: "3.5"},
+            )
+            self.assertEqual(response.status, 204)
+            response = await client.post(
+                "/",
+                data=(
+                    "def f(\n"
+                    "    and_has_a_bunch_of,\n"
+                    "    very_long_arguments_too,\n"
+                    "    and_lots_of_them_as_well_lol,\n"
+                    "    **and_very_long_keyword_arguments\n"
+                    "):\n"
+                    "    pass\n"
+                ),
+                headers={blackd.PYTHON_VARIANT_HEADER: "2"},
+            )
+            self.assertEqual(response.status, 204)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_fast(self) -> None:
+        with open(os.devnull, "w") as dn, redirect_stderr(dn):
+            app = blackd.make_app()
+            async with TestClient(TestServer(app)) as client:
+                response = await client.post("/", data=b"ur'hello'")
+                self.assertEqual(response.status, 500)
+                self.assertIn("failed to parse source file", await response.text())
+                response = await client.post(
+                    "/", data=b"ur'hello'", headers={blackd.FAST_OR_SAFE_HEADER: "fast"}
+                )
+                self.assertEqual(response.status, 200)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_line_length(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/", data=b'print("hello")\n', headers={blackd.LINE_LENGTH_HEADER: "7"}
+            )
+            self.assertEqual(response.status, 200)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    @async_test
+    async def test_blackd_invalid_line_length(self) -> None:
+        app = blackd.make_app()
+        async with TestClient(TestServer(app)) as client:
+            response = await client.post(
+                "/",
+                data=b'print("hello")\n',
+                headers={blackd.LINE_LENGTH_HEADER: "NaN"},
+            )
+            self.assertEqual(response.status, 400)
+
+    @unittest.skipUnless(has_blackd_deps, "blackd's dependencies are not installed")
+    def test_blackd_main(self) -> None:
+        with patch("blackd.web.run_app"):
+            result = CliRunner().invoke(blackd.main, [])
+            if result.exception is not None:
+                raise result.exception
+            self.assertEqual(result.exit_code, 0)
+

 
 if __name__ == "__main__":
     unittest.main(module="test_black")
 
 if __name__ == "__main__":
     unittest.main(module="test_black")