'Create and save a new OutcomeService model in the test database. The
OutcomeService model requires an LtiConsumer model, so we create one of
those as well. The method takes an ID string that is used to ensure that
unique fields do not conflict.'

def create_outcome_service(self, id_suffix):

    lti_consumer = LtiConsumer(consumer_name=('lti_consumer_name' + id_suffix), consumer_key=('lti_consumer_key' + id_suffix), consumer_secret=('lti_consumer_secret' + id_suffix), instance_guid=('lti_instance_guid' + id_suffix))
    lti_consumer.save()
    outcome_service = OutcomeService(lis_outcome_service_url=('https://example.com/outcomes/' + id_suffix), lti_consumer=lti_consumer)
    outcome_service.save()
    return outcome_service
