<int> mock;    EXPECT_CALL(mock, GetSize())       .WillOnce(Return(0))       .WillOnce(Return(0))       .WillOnce(Return(0));   EXPECT_CALL(mock, Push(_));   int n = 0;   EXPECT_CALL(mock, GetTop())       .WillOnce(ReturnRef(n));   EXPECT_CALL(mock, Pop())       .Times(AnyNumber());    EXPECT_EQ(0, mock.GetSize());   mock.Push(0);   EXPECT_EQ(0, mock.GetSize());   EXPECT_EQ(0, mock.GetTop());   mock.Pop();   EXPECT_EQ(0, mock.GetSize()); } 