如何在GMock EXPECT_CALL中模拟函数参数的引用参数值

Question

我刚刚开始谷歌模拟并尝试编写第一个模拟测试，如下所示。 AWSS3io是一个rest API类，用于与AWS s3服务器通信以获取文件。我想测试-ve场景，即500响应代码。您能否提供有价值的评论，这些代码很好，或者还有其他方法可以让您更优雅。

================以下是代码。===================

File: AWSS3io.h
---------------------------start-----------------------------------
class AWSS3io  {
        private:
            std::string m_aws_url;

        public:
            IO_STATUS_CODE get(const std::string &key, std::string &output_string, int &resp_code);
            AWSS3io(const std::string &  aws_url);
            ~AWSS3io();
    };
#if GTEST
class MockAWSS3io
    {
        private:
            std::string m_aws_url;

        public:
            MockAWSS3io(const std::string & aws_url) { m_aws_url = aws_url; }
            ~MockAWSS3io() {}
            MOCK_METHOD3(get, IO_STATUS_CODE(const std::string &key, std::string &output_string, int &resp_code));
    };
#endif
    class AWSio
    {
        public:
             AWSio(AWSS3io* paws);
            ~AWSio();
            IO_STATUS_CODE get(const std::string &key, std::string &output_string);
#if GTEST
            MockAWSS3io* aws_s3_io = nullptr;
#else
            AWSS3io* aws_s3_io = nullptr;
#endif
    };
---------------------------end-----------------------------------

file: tests/test_aws_mock_test.cpp
---------------------------start-----------------------------------
TEST(FileGetTest, FailureCase) {
    const std::string t_aws_url = "aa.s3.awss3.com";
    MockAWSS3io aws_s3_io(t_aws_url);
    EXPECT_CALL(*aws_s3_io, get(_,_,_))
    .Times(AtLeast(2)).WillOnce(testing::SetArgReferee<2>(500)).WillRepeatedly(testing::SetArgReferee<2>(200));

    AWSio awsio(&aws_s3_io);
    std::string key, value;
    EXPECT_TRUE(awsio.get(key, value));
}

int main(int argc, char** argv) {
  ::testing::InitGoogleMock(&argc, argv);
  return RUN_ALL_TESTS();
}
---------------------------end-----------------------------------