def test_duration_attribute_is_negative(self):
        d =  DurationMixin(duration=10)

        with self.assertRaises(ValueError) as cm:
            d.duration = -10

        self.assertEqual(
            cm.exception.message,
            'DurationMixin.duration should be an non-negative float'
        )
testing if a ValueError will be raised when the duration attribute
dataset/ETHPy150Open eoyilmaz/anima/tests/previs/test_duration_mixin.py/DurationAttrMixinTestCase.test_duration_attribute_is_negative