'Assert field threw a validation error
response
Client response object
field
Field name to test for validation error
match
Regex match for field validation error'

def assertWizardFailure(self, response, field, match=None):

    self.assertEqual(response.status_code, 200)
    self.assertIn('wizard', response.context_data)
    self.assertIn('form', response.context_data['wizard'])
    self.assertIn(field, response.context_data['wizard']['form'].errors)
    if (match is not None):
        error = response.context_data['wizard']['form'].errors[field]
        self.assertRegexpMatches(six.text_type(error), match)
