final CurlResponse mockResponse = createMockResponse(200, opJson);

        // Use a subclass to mock both CurlHelper access and getActiveInstances
        final CoordinatorHelper helper = new CoordinatorHelper() {
            @Override
            public List<InstanceInfo> getActiveInstances() {
                final InstanceInfo info = new InstanceInfo();
                info.instanceId = "node1@host1";