期待来自另一个线程的 googlemock 调用

Expecting googlemock calls from another thread(期待来自另一个线程的 googlemock 调用)

问题描述

使用 google 模拟对象编写 (google) 测试用例并期望从测试中的类控制的另一个线程调用 EXPECT_CALL() 定义的最佳方法是什么?在触发调用序列后简单地调用 sleep() 或类似方法并不合适，因为它可能会减慢不必要的测试并且可能不会真正达到计时条件.但是以某种方式完成测试用例必须等到模拟方法被调用.有什么想法吗?

What will be the best way to write (google) test cases using a google mock object and expect the EXPECT_CALL() definitions being called from another thread controlled by the class in test? Simply calling sleep() or alike after triggering the call sequences doesn't feel appropriate since it may slow down testing unnecessary and may not really hit the timing conditions. But finishing the test case somehow has to wait until the mock methods have been called. Ideas anyone?

这里有一些代码来说明这种情况:

Here's some code to illustrate the situation:

Bar.hpp(被测类)

Bar.hpp (the class under test)

class Bar
{
public:

Bar(IFooInterface* argFooInterface);
virtual ~Bar();

void triggerDoSomething();
void start();
void stop();

private:
void* barThreadMethod(void* userArgs);
void endThread();
void doSomething();

ClassMethodThread<Bar> thread; // A simple class method thread implementation using boost::thread
IFooInterface* fooInterface;
boost::interprocess::interprocess_semaphore semActionTrigger;
boost::interprocess::interprocess_semaphore semEndThread;
bool stopped;
bool endThreadRequested;
};

Bar.cpp(摘录):

Bar.cpp (excerpt):

void Bar::triggerDoSomething()
{
    semActionTrigger.post();
}

void* Bar::barThreadMethod(void* userArgs)
{
    (void)userArgs;
    stopped = false;
    do
    {
        semActionTrigger.wait();
        if(!endThreadRequested && !semActionTrigger.try_wait())
        {
            doSomething();
        }
    } while(!endThreadRequested && !semEndThread.try_wait());
    stopped = true;
    return NULL;
}

void Bar::doSomething()
{
    if(fooInterface)
    {
        fooInterface->func1();
        if(fooInterface->func2() > 0)
        {
            return;
        }
        fooInterface->func3(5);
    }
}

测试代码(摘录，到目前为止 FooInterfaceMock 的定义没有什么特别之处):

The testing code (excerpt, nothing special in the definition of FooInterfaceMock so far):

class BarTest : public ::testing::Test
{
public:

    BarTest()
    : fooInterfaceMock()
    , bar(&fooInterfaceMock)
    {
    }

protected:
    FooInterfaceMock fooInterfaceMock;
    Bar bar;
};

TEST_F(BarTest, DoSomethingWhenFunc2Gt0)
{
    EXPECT_CALL(fooInterfaceMock,func1())
        .Times(1);
    EXPECT_CALL(fooInterfaceMock,func2())
        .Times(1)
        .WillOnce(Return(1));

    bar.start();
    bar.triggerDoSomething();
    //sleep(1);
    bar.stop();
}

没有 sleep() 的测试结果:

Test results without sleep():

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from BarTest
[ RUN      ] BarTest.DoSomethingWhenFunc2Gt0
../test/BarTest.cpp:39: Failure
Actual function call count doesn't match EXPECT_CALL(fooInterfaceMock, func2())...
         Expected: to be called once
           Actual: never called - unsatisfied and active
../test/BarTest.cpp:37: Failure
Actual function call count doesn't match EXPECT_CALL(fooInterfaceMock, func1())...
         Expected: to be called once
           Actual: never called - unsatisfied and active
[  FAILED  ] BarTest.DoSomethingWhenFunc2Gt0 (1 ms)
[----------] 1 test from BarTest (1 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] BarTest.DoSomethingWhenFunc2Gt0

 1 FAILED TEST
terminate called after throwing an instance of         'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::lock_error> >'
Aborted

启用 sleep() 的测试结果:

Test results with sleep() enabled:

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from BarTest
[ RUN      ] BarTest.DoSomethingWhenFunc2Gt0
[       OK ] BarTest.DoSomethingWhenFunc2Gt0 (1000 ms)
[----------] 1 test from BarTest (1000 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1000 ms total)
[  PASSED  ] 1 test.

我想避免 sleep()，最好的情况是根本不需要更改 Bar 类.

I want to avoid the sleep(), in best case without need to change the Bar class at all.

推荐答案

Fraser 的回答启发了我使用 GMock 专用 Action 的简单解决方案.GMock 使得快速编写此类动作变得非常容易.

Fraser's answer inspired me for a simple solution using a GMock specialized Action. GMock makes it very easy to quickly write such Actions.

这是代码(摘自 BarTest.cpp):

Here's the code (excerpt from BarTest.cpp):

// Specialize an action that synchronizes with the calling thread
ACTION_P2(ReturnFromAsyncCall,RetVal,SemDone)
{
    SemDone->post();
    return RetVal;
}

TEST_F(BarTest, DoSomethingWhenFunc2Gt0)
{
    boost::interprocess::interprocess_semaphore semDone(0);
    EXPECT_CALL(fooInterfaceMock,func1())
        .Times(1);
    EXPECT_CALL(fooInterfaceMock,func2())
        .Times(1)
        // Note that the return type doesn't need to be explicitly specialized
        .WillOnce(ReturnFromAsyncCall(1,&semDone));

    bar.start();
    bar.triggerDoSomething();
    boost::posix_time::ptime until = boost::posix_time::second_clock::universal_time() +
            boost::posix_time::seconds(1);
    EXPECT_TRUE(semDone.timed_wait(until));
    bar.stop();
}

TEST_F(BarTest, DoSomethingWhenFunc2Eq0)
{
    boost::interprocess::interprocess_semaphore semDone(0);
    EXPECT_CALL(fooInterfaceMock,func1())
        .Times(1);
    EXPECT_CALL(fooInterfaceMock,func2())
        .Times(1)
        .WillOnce(Return(0));
    EXPECT_CALL(fooInterfaceMock,func3(Eq(5)))
        .Times(1)
        // Note that the return type doesn't need to be explicitly specialized
        .WillOnce(ReturnFromAsyncCall(true,&semDone));

    bar.start();
    bar.triggerDoSomething();
    boost::posix_time::ptime until = boost::posix_time::second_clock::universal_time() +
            boost::posix_time::seconds(1);
    EXPECT_TRUE(semDone.timed_wait(until));
    bar.stop();
}

请注意，与 boost::interprocess::interprocess_semaphore 一样，同样的原则也适用于任何其他类型的信号量实现.我用它来测试我们的生产代码，这些代码使用它自己的操作系统抽象层和信号量实现.

Note the same principle will work well for any other kind of semaphore implementation as boost::interprocess::interprocess_semaphore. I'm using it for testing with our production code that uses it's own OS abstraction layer and semaphore implementation.

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