Prevent Moq from creating singleton Mocks

Question

It seems like mocked services are being shared with consumers, as if the mocked interfaces are singleton. I'm using AutoMoq/Moq combination if that's relevant.

class TestableClass 
{ 
    public IService service; 
    public TestableClass(IService s) { this.service = s }
}

Mocker.GetMock<IService>.Setup(s => s.Do()).Returns(1);
var c1 = Mocker.Resolve<TestableClass>();
var c2 = Mocker.Resolve<TestableClass>();
Assert.That(c1, Is.Not.SameAs(c2)); // true
Assert.That(c1.service, Is.NotSameAs(c2.service)) // false/fail

Is there a way to ensure that IService is a different instance each time a consuming instance is created? The reason being:

Mocker.GetMock<IPauseTimer>()
    .Setup(t => t.Begin(20))
    .Raises(t => t.Tick += null, new PauseTimerEventArgs(1))
    .Verifiable();

When I create my two test instances, they share this single PauseTimer, and when c1 triggers the Begin function, both c1 and c2 react to the event, when only c1 should.

I understand the problem (and your work-around solution). But it's hard to understand what you're actually testing. How does `PauseTimer` fit in to the TestableClass above? Are you sure you're writing your test in the best possible way? This problem gives me a feeling something is a bit strange here. — MEMark, Sep 02 '14 at 19:42
@MEMark The original purpose of the test was for verifying synchronisation. The timer should not be shared, but the `TestableClass` should send a message to the other `TestableClass` so that the timer state can synchronise. Basically, there is a stop watch in each class, but only one stop watch is triggered, which should update the UI of both. The stop watch can't be singleton, because there can be multiple pairs throughout the program. — Josh Smeaton, Sep 02 '14 at 21:36

score 1 · Accepted Answer · answered Dec 02 '13 at 05:01

I worked around it by creating another mocking container, which ensures the instances are not the same reference.

var otherMocker = new AutoMoqer();
Mocker.GetMock<IService>.Setup(s => s.Do()).Returns(1);
otherMocker.GetMock<IService>.Setup(s => s.Do()).Returns(1);
var c1 = Mocker.Resolve<TestableClass>();
var c2 = otherMocker.Resolve<TestableClass>();
Assert.That(c1, Is.Not.SameAs(c2)); // true
Assert.That(c1.service, Is.NotSameAs(c2.service)) // true

This is not really desirable, as all the setup work needed to be replicated on this other container. A helper method helps:

[SetUp]
public void Setup()
{
    Mocker = GetMoqer();
}

AutoMoqer GetMoqer() 
{ 
    // configure base Mocker 
    return new AutoMoqer();
}

[Test]
public void TestWithDifferentInstances()
{
    var s1 = Mocker.ResolveMock<IService>();
    var otherMocker = GetMoqer();
    var s2 = otherMocker.ResolveMock<IService>();
    Assert.That(s1, Is.Not.SameAs(s2));
}

Quite happy to accept an answer other than this one if there's a simpler method. — Josh Smeaton, Dec 02 '13 at 05:08

Prevent Moq from creating singleton Mocks

1 Answers1