add a MockResponse

tests/mocks.py

@@ -0,0 +1,12 @@
+import json
+
+
+class MockResponse:
+
+    def __init__(self, data):
+        self.data = data
+
+    # mock json() method always returns a specific testing dictionary
+    # @staticmethod
+    def json(self):
+        return json.loads(self.data)