Problem verifying arguments

/* class that I am going to fake in my tests */
class ClassUnderTest
{
    internal ClassUnderTest()      {}
    internal ClassUnderTest(int i) {}
}

/* class faking ClassUnderTest that checks the parameters of the ctor */
class FakeClassUnderTest
{
    private Mock _mock = null;

    internal FakeOfToFake(params object[] args)
    {
        _mock = MockManager.Mock(typeof(ClassUnderTest));
        _mock.ExpectConstructor().Args(args);
    }
}


[Test]
public void TestConstructorTooParams()
{
    FakeClassUnderTest fake = new FakeClassUnderTest (1);
    ClassUnderTest classUnderTest = new ClassUnderTest();

    /* this test fail because 1 param is expected but constructor is called with 0 -> ok */
}

[Test]
public void TestConstructorTooFewParams()
{
    FakeClassUnderTest fake = new FakeClassUnderTest ();
    ClassUnderTest classUnderTest = new ClassUnderTest(1);

    /* this test succeeds while I expected to fail for a mismatch in the number of parameters */
}