def test_model_field_default_info():
    """Test that __repr_args__ of FieldInfo includes the default value when it's set to None."""

    class Model(BaseModel):
        a: Union[int, None] = Field(default=None)
        b: Union[int, None] = None

    assert str(Model.model_fields) == (
        "{'a': FieldInfo(annotation=Union[int, NoneType], required=False, default=None), "
        "'b': FieldInfo(annotation=Union[int, NoneType], required=False, default=None)}"
    )
Test that __repr_args__ of FieldInfo includes the default value when it's set to None.
tests/test_fields.py