def METHOD_NAME(self):
    # Arrange
    test_data = [
        "event_start",  # single _ instead of double __
        "-event__end",
        "proximity",
        " event__start",  # space
        "calculated_priority",  # unavailable
    ]
    filterset = InstructorRecruitmentFilter({})
    field = filterset.filters["order_by"].field
    # Act
    for value in test_data:
        with self.subTest(value=value):
            # Assert
            with self.assertRaises(ValidationError):
                field.validate(value)