Invoking public method on mocked instance invalidates mock setup on protected method

[paulomorgado]

Version: 4.6.38-alpha
Project: .NET Core class library

I have this test that works just fine:

[Fact]
public async Task EventStateBaseWithoutEventTransitions_WithoutCancellation_ReturnsReturnValueOfExecuteEventStepAsync()
{
    var logger = new TestLogger();

    var stateTransition = new Transition("Targeted", Mock.Of<TransitionTarget>(), logger.TransitionAction, null);

    var stateMock = new Mock<EventStateBase>(
        "test",
        logger.StateEnterAction,
        logger.StateExitAction,
        logger.StateCancelledAction)
    {
        CallBase = true,
    };

    stateMock.Protected()
        .Setup<Task<Transition>>("ExecuteEventStepAsync", It.IsAny<CancellationToken>())
        .ReturnsAsync(stateTransition);

    var actual = await stateMock.Object.ExecuteAsync(CancellationToken.None);

    Assert.Equal(stateTransition, actual);
    Assert.Equal(">test;<test;", logger.ToString());

    stateMock.Protected().Verify<Task<Transition>>("ExecuteEventStepAsync", Times.Once(), It.IsAny<CancellationToken>());
}

But if I add a call to a public method of the mocked instance, the setup is ignored and the mock will return the default value and, on verification, is reported as not having been called.

It happens with this test, for example:

[Fact]
public async Task EventStateBaseWithEventTransitions_WithoutCancellationWithoutTriggeredEventTransitionAndStateExecutionReturningNull_DoesntCompleteExecution()
{
    var logger = new TestLogger();

    var eventName = "event";

    var eventTransition = new Transition("Event", Mock.Of<TransitionTarget>(), logger.TransitionAction, null);

    var stateMock = new Mock<EventStateBase>(
        "test",
        logger.StateEnterAction,
        logger.StateExitAction,
        logger.StateCancelledAction)
    {
        CallBase = true,
    };

    stateMock.Protected()
        .Setup<Task<Transition>>("ExecuteEventStepAsync", It.IsAny<CancellationToken>())
        .ReturnsAsync(null);

    stateMock.Object.AddEventTransition(eventName, eventTransition);

    var executeTask = stateMock.Object.ExecuteAsync(CancellationToken.None);

    Assert.False(executeTask.IsCompleted);
    Assert.Equal(">test;", logger.ToString());

    stateMock.Protected().Verify<Task<Transition>>("ExecuteEventStepAsync", Times.Once(), It.IsAny<CancellationToken>());
}

What am I doing wrong?

[stakx]

Could you please provide a short but complete repro code? It would be easier to look into this if one didn't have to guess at all the types and symbols not defined here. Thank you!

[stakx]

Closing for now due to inactivity. @paulomorgado, if you'd like to continue this, just report back with complete repro code and we can reopen.