Add BaseTestCase, use app generated in aura module

tests/__init__.py

+import logging
+
+from flask_testing import TestCase
+
+from aura_engine_api.app import app
+from aura_engine_api.rest.encoder import JSONEncoder
+
+
+class BaseTestCase(TestCase):
+    def create_app(self):
+        logging.getLogger("connexion.operation").setLevel("ERROR")
+        app.json_encoder = JSONEncoder
+        return app