How to verify ThreadPool execute method which takes Lambda as parameter

Question

I am currently testing a method in which I execute a runnable into a ThreadPool.

Here is the code for the method.

@Override
public void queueLogin(Connection connection, LoginPacket packet) {
    if(isRunning)
        loginPool.execute(() -> loginService.tryLogin(connection, packet));
}

Now I need to verify whether the execute method was invoked or not with the correct parameters.

Here is my test case

@Test
public void theQueueLoginShouldCallExecuteOnThreadPoolIfManagerIsRunning() {
    //Arrange
    loginManager.start();

    //Act
    loginManager.queueLogin(moqConnection, moqLoginPacket);

    //Assert
    verify(moqLoginPool).execute(() -> moqLoginService.tryLogin(moqConnection, moqLoginPacket));
}

But the test is failing saying

Argument(s) are different! Wanted:
executorService.execute(
    com.battletanks.game.server.unittests.manager.login.LoginManagerTests$$Lambda$2/1668016508@3d51f06e
);
-> at com.battletanks.game.server.unittests.manager.login.LoginManagerTests.theQueueLoginShouldCallExecuteOnThreadPoolIfManagerIsNotRunning(LoginManagerTests.java:84)
Actual invocation has different arguments:
executorService.execute(
    com.battletanks.game.server.manager.login.DefaultLoginManager$$Lambda$1/77269878@7ed7259e
);

I understand what is wrong here but I am not sure how to fix this.

Answer 1

The way you have it, you're relying on these two lambdas to be equal to one another. Because they don't have an overridden equals method, and are not the same instance, you won't be able to verify that way.

Instead, capture the argument , run it, and see that it does what you want it to do.

ArgumentCaptor<Runnable> runnableCaptor = ArgumentCaptor.for(Runnable.class);
verify(moqLoginPool).execute(runnableCaptor.capture());

verify(moqLoginService, never()).tryLogin(any(), any());
runnableCaptor.getValue().run();
verify(moqLoginService).tryLogin(any(), any());

Answer 2

如何验证是否使用任何参数调用了moqLoginPool）.execute（），然后确保执行完成后使用moqConnection，moqLoginPacket调用moqLoginService.tryLogin（）？