Improve v test coverage

tests/test_v.py

@@ -15,14 +15,15 @@
 
 from cattrs import Converter, transform_error
 from cattrs._compat import Mapping, TypedDict
+from cattrs.errors import IterableValidationError
 from cattrs.gen import make_dict_structure_fn
 from cattrs.v import format_exception
 
 
 @fixture
 def c() -> Converter:
     """We need only converters with detailed_validation=True."""
-    return Converter()
+    return Converter(detailed_validation=True)
 
 
 def test_attribute_errors(c: Converter) -> None:
@@ -190,6 +191,11 @@ class C:
             "invalid value for type, expected int @ $.b[1][2]",
         ]
 
+    # IterableValidationErrors with subexceptions without notes
+    exc = IterableValidationError("Test", [TypeError("Test")], list[str])
+
+    assert transform_error(exc) == ["invalid type (Test) @ $"]
+
 
 def test_mapping_errors(c: Converter) -> None:
     try: