Leaked Google Mock Object Does not Fail

Question

I came across some odd behavior when mocking a c++ destructor, as documented in google mock cookbook. The class and mock are as follows:

// System under test
class Base {
public: 
    virtual ~Base(){};
};

// Mocked class
class MockBase : public Base { 
public: 
    MOCK_METHOD0(Die, void());
    virtual ~MockBase() { Die(); }
};

Test 1. Test that a mock object is destructed once. This test passes just fine.

// Test 1. 
MockBase * mb1 = new MockBase(); 
EXPECT_CALL(*mb1, Die()).Times(1);
delete mb1;

Test 2. Expecting an object to be destructed twice, fails. This also makes sense.

// Test 2. This fails -> ok.
MockBase * mb2 = new MockBase(); 
EXPECT_CALL(*mb2, Die()).Times(2);
delete mb2;

Test 3. Testing that a non-deleted object is destructed. This test does not seem to fail, even though I expected it to fail. (notice that I commented out the delete command). At the end of the program, there are warnings that some mocked objects are never deleted.

// Test 3. This does not fail
MockBase * mb3 = new MockBase(); 
EXPECT_CALL(*mb3, Die()).Times(1);
//delete mb3;

Test 4. Testing that a non-deleted object is destructed twice. This test does not seem to fail either. Similar to test 3, I didn't delete this mockBase either, so I'd expect this to fail as well. I even increased the number of times that I expect this to be called, but it still doesn't fail.

// This does not fail
MockBase * mb4 = new MockBase(); 
EXPECT_CALL(*mb4, Die()).Times(2);
//delete mb4;

Can someone explain why Tests 3 and 4 pass?

Answer 1

From the Google Mock Cheat Sheet:

Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier

In other words, Test 3 and 4 in your examples never have their expectations verified because the mock object doesn't get destroyed. As per the Cheat Sheet, you can force the expectations to be verified manually. For example, Test 3 becomes the following:

MockBase * mb3 = new MockBase();
EXPECT_CALL(*mb3, Die());
Mock::VerifyAndClearExpectations(mb3);