public void TestMethod1()
{
A a = new A();
a.a = 10;
a.b = 12;
MyInterface myInterface = MockRepository.Mock <MyInterface>();
myInterface.Expect(x => x.retValue(Arg <A> .Matches(m => m.a == 10 && m.b == 12)))
.Return(5);
int ret = myInterface.retValue(a);
Assert.True(ret == 5);
myInterface.VerifyExpectations(true);
}