Add return type to tests without arguments (#87613)

* Add return type to tests without arguments

* Black

* Cancel fixture amends

tests/util/test_init.py

@@ -8,7 +8,7 @@ from homeassistant import util
 import homeassistant.util.dt as dt_util
 
 
-def test_raise_if_invalid_filename():
+def test_raise_if_invalid_filename() -> None:
     """Test raise_if_invalid_filename."""
     assert util.raise_if_invalid_filename("test") is None
 
@@ -25,7 +25,7 @@ def test_raise_if_invalid_filename():
         util.raise_if_invalid_filename("\\../test")
 
 
-def test_raise_if_invalid_path():
+def test_raise_if_invalid_path() -> None:
     """Test raise_if_invalid_path."""
     assert util.raise_if_invalid_path("test/path") is None
 
@@ -36,7 +36,7 @@ def test_raise_if_invalid_path():
         assert util.raise_if_invalid_path("~/../test/path")
 
 
-def test_slugify():
+def test_slugify() -> None:
     """Test slugify."""
     assert util.slugify("T-!@#$!#@$!$est") == "t_est"
     assert util.slugify("Test More") == "test_more"
@@ -61,7 +61,7 @@ def test_slugify():
     assert util.slugify(None) == ""
 
 
-def test_repr_helper():
+def test_repr_helper() -> None:
     """Test repr_helper."""
     assert util.repr_helper("A") == "A"
     assert util.repr_helper(5) == "5"
@@ -76,7 +76,7 @@ def test_repr_helper():
         )
 
 
-def test_convert():
+def test_convert() -> None:
     """Test convert."""
     assert util.convert("5", int) == 5
     assert util.convert("5", float) == 5.0
@@ -86,13 +86,13 @@ def test_convert():
     assert util.convert(object, int, 1) == 1
 
 
-def test_ensure_unique_string():
+def test_ensure_unique_string() -> None:
     """Test ensure_unique_string."""
     assert util.ensure_unique_string("Beer", ["Beer", "Beer_2"]) == "Beer_3"
     assert util.ensure_unique_string("Beer", ["Wine", "Soda"]) == "Beer"
 
 
-def test_throttle():
+def test_throttle() -> None:
     """Test the add cooldown decorator."""
     calls1 = []
     calls2 = []
@@ -145,7 +145,7 @@ def test_throttle():
     assert len(calls2) == 2
 
 
-def test_throttle_per_instance():
+def test_throttle_per_instance() -> None:
     """Test that the throttle method is done per instance of a class."""
 
     class Tester:
@@ -160,7 +160,7 @@ def test_throttle_per_instance():
     assert Tester().hello()
 
 
-def test_throttle_on_method():
+def test_throttle_on_method() -> None:
     """Test that throttle works when wrapping a method."""
 
     class Tester:
@@ -177,7 +177,7 @@ def test_throttle_on_method():
     assert throttled() is None
 
 
-def test_throttle_on_two_method():
+def test_throttle_on_two_method() -> None:
     """Test that throttle works when wrapping two methods."""
 
     class Tester: