Add regression test for optional normalisation

Also runs black on the tests file

tests/test_utils.py

@@ -38,9 +38,7 @@ def test_cached_properties():
 
     # cached_slot_property
     class TestSlotted:
-        __slots__ = (
-            '_cs_time'
-        )
+        __slots__ = '_cs_time'
 
         @utils.cached_slot_property('_cs_time')
         def time(self) -> float:
@@ -61,7 +59,7 @@ def test_cached_properties():
         (123456789012345678, (2015, 12, 7, 16, 13, 12)),
         (661720302316814366, (2020, 1, 1, 0, 0, 14)),
         (1000000000000000000, (2022, 7, 22, 11, 22, 59)),
-    ]
+    ],
 )
 def test_snowflake_time(snowflake: int, time_tuple: typing.Tuple[int, int, int, int, int, int]):
     dt = utils.snowflake_time(snowflake)
@@ -74,10 +72,7 @@ def test_snowflake_time(snowflake: int, time_tuple: typing.Tuple[int, int, int,
 @pytest.mark.asyncio
 async def test_get_find():
     # Generate a dictionary of random keys to values
-    mapping = {
-        secrets.token_bytes(32): secrets.token_bytes(32)
-        for _ in range(100)
-    }
+    mapping = {secrets.token_bytes(32): secrets.token_bytes(32) for _ in range(100)}
 
     # Turn it into a shuffled iterable of pairs
     pair = collections.namedtuple('pair', 'key value')
@@ -136,7 +131,7 @@ def test_valid_icon_size():
         ('https://discordapp.com/invite/dpy', 'dpy'),
         ('https://discord.com/invite/dpy', 'dpy'),
         ('https://discord.gg/dpy', 'dpy'),
-    ]
+    ],
 )
 def test_resolve_invite(url, code):
     assert utils.resolve_invite(url).code == code
@@ -148,16 +143,13 @@ def test_resolve_invite(url, code):
         ('https://discordapp.com/template/foobar', 'foobar'),
         ('https://discord.com/template/foobar', 'foobar'),
         ('https://discord.new/foobar', 'foobar'),
-    ]
+    ],
 )
 def test_resolve_template(url, code):
     assert utils.resolve_template(url) == code
 
 
-@pytest.mark.parametrize(
-    'mention',
-    ['@everyone', '@here']
-)
+@pytest.mark.parametrize('mention', ['@everyone', '@here'])
 def test_escape_mentions(mention):
     assert mention not in utils.escape_mentions(mention)
     assert mention not in utils.escape_mentions(f"one {mention} two")
@@ -171,7 +163,7 @@ def test_escape_mentions(mention):
         ([1, 2, 3, 4, 5, 6], 3, [[1, 2, 3], [4, 5, 6]]),
         ([1, 2, 3, 4, 5, 6], 4, [[1, 2, 3, 4], [5, 6]]),
         ([1, 2, 3, 4, 5, 6], 5, [[1, 2, 3, 4, 5], [6]]),
-    ]
+    ],
 )
 async def test_as_chunks(source, chunk_size, chunked):
     assert [x for x in utils.as_chunks(source, chunk_size)] == chunked
@@ -185,12 +177,17 @@ async def test_as_chunks(source, chunk_size, chunked):
         ('datetime.datetime', datetime.datetime),
         ('typing.Union[typing.Literal["a"], typing.Literal["b"]]', typing.Union[typing.Literal["a"], typing.Literal["b"]]),
         ('typing.Union[typing.Union[int, str], typing.Union[bool, dict]]', typing.Union[int, str, bool, dict]),
-    ]
+    ],
 )
 def test_resolve_annotation(annotation, resolved):
     assert resolved == utils.resolve_annotation(annotation, globals(), locals(), None)
 
 
+def test_resolve_annotation_optional_normalisation():
+    value = utils.resolve_annotation('typing.Union[None, int]', globals(), locals(), None)
+    assert value.__args__ == (int, type(None))
+
+
 @pytest.mark.skipif(sys.version_info < (3, 10), reason="3.10 union syntax")
 @pytest.mark.parametrize(
     ('annotation', 'resolved'),
@@ -198,7 +195,7 @@ def test_resolve_annotation(annotation, resolved):
         ('int | None', typing.Optional[int]),
         ('str | int', typing.Union[str, int]),
         ('str | int | None', typing.Optional[typing.Union[str, int]]),
-    ]
+    ],
 )
 def test_resolve_annotation_310(annotation, resolved):
     assert resolved == utils.resolve_annotation(annotation, globals(), locals(), None)
@@ -206,27 +203,33 @@ def test_resolve_annotation_310(annotation, resolved):
 
 # is_inside_class tests
 
+
 def not_a_class():
     def not_a_class_either():
         pass
+
     return not_a_class_either
 
+
 class ThisIsAClass:
     def in_a_class(self):
         def not_directly_in_a_class():
             pass
+
         return not_directly_in_a_class
 
     @classmethod
     def a_class_method(cls):
         def not_directly_in_a_class():
             pass
+
         return not_directly_in_a_class
 
     @staticmethod
     def a_static_method():
         def not_directly_in_a_class():
             pass
+
         return not_directly_in_a_class
 
     class SubClass:
@@ -255,7 +258,7 @@ def test_is_inside_class():
         (datetime.datetime(2020, 1, 1, 0, 0, 0, 0, tzinfo=datetime.timezone.utc), None, '<t:1577836800>'),
         (datetime.datetime(2020, 1, 1, 0, 0, 0, 0, tzinfo=datetime.timezone.utc), 'F', '<t:1577836800:F>'),
         (datetime.datetime(2033, 5, 18, 3, 33, 20, 0, tzinfo=datetime.timezone.utc), 'D', '<t:2000000000:D>'),
-    ]
+    ],
 )
 def test_format_dt(dt: datetime.datetime, style: typing.Optional[utils.TimestampStyle], formatted: str):
     assert utils.format_dt(dt, style=style) == formatted