Improve disambiguators coverage

Author: Tinche

tests/test_disambiguators.py

@@ -130,10 +130,7 @@ class A:
     assert fn({}) is A
     assert fn(asdict(cl(*vals, **kwargs))) is cl
 
-    attr_names = {a.name for a in fields(cl)}
-
-    if "xyz" not in attr_names:
-        assert fn({"xyz": 1}) is A  # Uses the fallback.
+    assert fn({"xyz": 1}) is A  # Uses the fallback.
 
 
 @settings(suppress_health_check=[HealthCheck.filter_too_much, HealthCheck.too_slow])

tests/untyped.py

@@ -167,7 +167,7 @@ def gen_attr_names() -> Iterable[str]:
 def _create_hyp_class(
     attrs_and_strategy: list[tuple[_CountingAttr, st.SearchStrategy[PosArgs]]],
     frozen=None,
-):
+) -> SearchStrategy[tuple]:
     """
     A helper function for Hypothesis to generate attrs classes.