refactor get() for multiple resources

tests/test_gce.py

@@ -50,11 +50,11 @@ def delete(self, *args, **kwargs):
                 return MockRequest(None)
         raise ValueError("Unexpected delete request")
 
-    def get(self, project, region):
-        def something():
-            pass
-        something.execute = lambda: self.responses
-        return something
+    def get(self, *args, **kwargs):
+        for resource in ('object', 'image', 'disk', 'instance', 'firewall', 'forwardingRule', 'route', 'network', 'subnetwork'):
+            if resource in kwargs:
+              return MockRequest(self.responses)
+            raise ValueError(f"Unexpected get request")
 
 
 class MockClient: