c++ - How to test a pure-virtual class without implementation? -

i have following class:

// ivirtualcontroller.hpp class ivirtualcontroller { public:   virtual inputcode validate(int keycode) = 0;   virtual ~ivirtualcontroller(); }; 

and want mock class:

// inputmanagertest.cpp class mockcontroller : public ivirtualcontroller { public:   mock_method1(validate,inputcode(int keycode)); }; 

but doesn't work! following errors:

test/input/inputmanagertest.o: in function mockcontroller::~mockcontroller()': test/input/inputmanagertest.cpp:19: undefined reference toivirtualcontroller::~ivirtualcontroller()' test/input/inputmanagertest.cpp:19: undefined reference `ivirtualcontroller::~ivirtualcontroller()'

test/input/inputmanagertest.o: in function ivirtualcontroller::ivirtualcontroller()': test/input/../../src/input/ivirtualcontroller.hpp:14: undefined reference tovtable ivirtualcontroller'

test/input/inputmanagertest.o: in function mockcontroller::mockcontroller()': test/input/inputmanagertest.cpp:15: undefined reference toivirtualcontroller::~ivirtualcontroller()'

test/input/inputmanagertest.o:(.rodata._zti14mockcontroller[_zti14mockcontroller]+0x10): undefined reference `typeinfo ivirtualcontroller'

a search told me "undefined reference vtable/typeinfo" errors caused missing implementation, missing "= 0" behind virtual method declaration or non-virtual destructor. class ivirtualcontroller isn't implemented, shouldn't problem since mockcontroller implementing it, right? commenting out whole inputmanagertest.cpp mock file "solves" problem, though ivirtualcontroller used in class.

how test it?

nope. destructor must implemented. pure virtual one.

that's because of how works. virtual applied destructor holds a different more meaning. usually, virtual method isn't called if it's overriden in derived class, virtual destructor still called, implementation required.

the =0 destructor makes class abstract, but, stated before, implementation still required.