Add simple validation test case

test.py

@@ -38,5 +38,25 @@ class TestBaseAPI(tornado.testing.AsyncHTTPTestCase):
             self.assertEqual(response.body.decode(), oas3f.read(), "OAS3 content differs from spec file!")
 
 
+class TestValidation(tornado.testing.AsyncHTTPTestCase):
+    """Validation test cases"""
+    def get_app(self):
+        return make_app()
+
+    def test_null_validation(self):
+        entity = {}
+
+        response = self.fetch('/v0/validate',
+                              method='POST',
+                              body=json.dumps(entity))
+
+        self.assertEqual(200, response.code, "Validation must always return 200")
+
+        validation_result = json.loads(response.body.decode())
+
+        self.assertIn('valid', validation_result, "Key 'valid' expected in validation result")
+        self.assertTrue(validation_result['valid'], "Validation result is expected to be valid==true")
+
+
 if __name__ == "__main__":
     unittest.main()