c++ - GMock 死亡案例 - 模拟函数未被调用

Question

1. 我在 my_inet.cpp 文件中创建了一个外部套接字 api 的模拟。
2. 该套接字 API 的 GMock 函数在 mock.h 文件中。
3. 我在 server.cpp 文件中使用我创建的 my_inet 套接字 api。
4. 测试用gtest.cpp编写。

这里写的死亡案例是按照输出执行的。输出表明该进程已终止。但它还表示从未进行过 socket() 调用，因此该案例显示为失败。

请问这是什么原因，解决方法是什么。

gtest.cpp

TEST(MyTest, SocketConnectionFail)
{
    MockMyTCPAPI obj_myTCP;

    EXPECT_CALL( obj_myTCP, socket( 1, 0, 0 ))
    .Times( 1 )
    .WillOnce( Return( -1 ));

    Server obj_server( &obj_myTCP );

    EXPECT_DEATH( obj_server.InitializeSocket(), "No socket connection!");
}

服务器.cpp

int Server::InitializeSocket()
{
  if( ret_val_socket == -1 )
  {
        ret_val_socket = myTCPAPI->socket( PF_INET, SOCK_STREAM, 0 );

        if( ret_val_socket == -1 )
        {
            printf( "\nNo socket connection!" );
            exit(1);
        }
        return ret_val_socket;
  }
  else
  {
        printf( "Warning! Attempting to create socket again. %d" , ret_val_socket);
        return 2;
  }

  return 0;
}

my_inet.cpp

int MyTCPAPI::socket( int arg1, int arg2, int arg3 )
{
        return -1;
}

输出:

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from MyTest
[ RUN      ] MyTest.SocketConnectionFail

[WARNING] /usr/src/gtest/src/gtest-death-test.cc:825:: Death tests use fork(), which is unsafe particularly in a threaded context. For this test, Google Test couldn't detect the number of threads.

No socket connection!
/home/../Documents/office/tdd/tcp/server/gtest.cpp:49: ERROR: this mock object (used in test MyTest.SocketConnectionFail) should be deleted but never is. Its address is @0x7fff2e94a890.
ERROR: 1 leaked mock object found at program exit.
/home/../Documents/office/tdd/tcp/server/gtest.cpp:56: Failure
Death test: obj_server.InitializeSocket()
    Result: died but not with expected error.
  Expected: No socket connection!
Actual msg:
[  DEATH   ] 
/home/../Documents/office/tdd/tcp/server/gtest.cpp:49: Failure
Actual function call count doesn't match EXPECT_CALL(obj_myTCP, socket( 1, 0, 0 ))...
         Expected: to be called once
           Actual: never called - unsatisfied and active
[  FAILED  ] MyTest.SocketConnectionFail (3 ms)
[----------] 1 test from MyTest (3 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (3 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] MyTest.SocketConnectionFail

 1 FAILED TEST

Answer 1

根据docs , EXPECT_DEATH 和 ASSERT_DEATH 产生一个执行死亡测试语句的子进程(在本例中为 obj_server.InitializeSocket())。

子进程终止后，他们检查退出代码和 stderr 消息。如果退出代码为0或stderr中的消息与预期值不匹配，则测试无效。另一方面，stdout 未被检查。

因此，printf( "\nNo socket connection!") 必须在应用程序之前替换为 fprintf(stderr, "\nNo socket connection!")导出:

int Server::InitializeSocket()
{
  if( ret_val_socket == -1 )
  {
        ret_val_socket = myTCPAPI->socket( PF_INET, SOCK_STREAM, 0 );

        if( ret_val_socket == -1 )
        {
            fprintf(stderr, "\nNo socket connection!" ); // print to stderr here
            exit(1);
        }
        return ret_val_socket;
  }
  else
  {
        printf( "Warning! Attempting to create socket again. %d" , ret_val_socket);
        return 2;
  }

  return 0;
}

---

正如评论中所指出的，EXPECT_CALL 将失败。在指定它可能被调用的次数时使用 AnyNumber 在这种情况下可能会有所帮助(只有第一次调用将返回 -1 并且测试用例可能仍然失败)。

测试(我的测试，套接字连接失败){MockMyTCPAPI obj_myTCP;

EXPECT_CALL( obj_myTCP, socket( 1, 0, 0 ))
.Times(testing::AnyNumber())
.WillOnce( Return( -1 ));

Server obj_server( &obj_myTCP );

EXPECT_DEATH( obj_server.InitializeSocket(), "No socket connection!");