Google mock: Mocking parent class? - c++

Question

Assume I have a base class:
class Command {
public:
virtual int8_t Execute();
};
with a definition in the base class cpp.
Additionally, I have a child class:
class SpecificCommand: public Command {
public:
int8_t Execute();
};
With the definition:
int8_t SpecificCommand::Execute() {
doSomeStuff();
Command::Execute();
}
How do I mock Command::Execute() but using a SpecificCommand object for tests?

Answer 1

Maybe something like that:
class SpecificCommandMock : public SpecificCommand
{
public:
MOCK_METHOD0(ExecuteMockedMethod, void());
int8_t Execute() override
{
doSomeStuff()
ExecuteMockedMethod();
}
}
Of course you should use SpecificCommandMock in unit tests and set EXPECT_CALL for ExecuteMockedMethod when class under test is expected to call Execute().
In addition I suppose that something could be wrong in design of the application if you have to do such things.

Answer 2

This should not be possible in the way you are expecting. I.e. gtest cannot just replace the part of your code and instead of:
int8_t SpecificCommand::Execute() {
doSomeStuff();
Command::Execute();
}
execute something like:
int8_t SpecificCommand::Execute() {
doSomeStuff();
}
You operate with macroses mainly which are just wrap your code with some other. So the language limitation still in there.
Some options (which don't affect your Command implementation):
if doSomeStuff is a public - override the Execute() with mock class as proposed by trivelt or do it like official docs suggests with ON_CALL declaration in mock constructor
write DummyCommand.cpp which do nothing and by compilation option build it instead of original one. In cmake it's if-else + add_library/add_executable manipulations.
write mock to the library which uses "network access that can not be tested" and link it instead of original one by compilation option. (if-else + target_link_library or even include manipulations in the cmake)
write mock for the network communication backend (web_server, etc)