def test_add_evidence(self):
        step_result = StepResult('step1', 'sub1', 'implementer1')
        step_result.add_evidence('evidence1', 'value1', 'description1')
        step_result.add_evidence('evidence2', 'value2', 'description2')
        step_result.add_evidence('evidence3', 'value3')

        self.assertEqual(
            step_result.get_evidence('evidence1'),
            StepResultEvidence(name='evidence1',
                               value='value1',
                               description='description1'))
        self.assertEqual(
            step_result.get_evidence('evidence2'),
            StepResultEvidence(name='evidence2',
                               value='value2',
                               description='description2'))
        self.assertEqual(step_result.get_evidence('evidence3'),
                         StepResultEvidence(name='evidence3', value='value3'))
    def test_get_evidence(self):
        expected_evidence = StepResultEvidence(name='evidence1',
                                               value='value1',
                                               description='description1')

        step_result = StepResult('step1', 'sub1', 'implementer1')
        step_result.add_evidence('evidence1', 'value1', 'description1')
        self.assertEqual(step_result.get_evidence('evidence1'),
                         expected_evidence)