def test_get_item_om_field(self):
        """
        REST Api: Test get item with O-M related field
        """
        client = self.app.test_client()
        token = self.login(client, USERNAME_ADMIN, PASSWORD_ADMIN)

        with model_om_parent_data(
            self.appbuilder.session, 1, MODELOMCHILD_DATA_SIZE
        ) as models:
            model_id = models[0].id
            rv = self.auth_client_get(
                client, token, "api/v1/modelomparentapi/{}".format(model_id)
            )
            data = json.loads(rv.data.decode("utf-8"))
            self.assertEqual(rv.status_code, 200)
            expected_rel_field = [
                {"field_string": child.field_string, "id": child.id}
                for child in models[0].children
            ]
            self.assertEqual(data[API_RESULT_RES_KEY]["children"], expected_rel_field)

        REST Api: Test get item with O-M related field
        
tests/test_api.py