HippoMocks - mocking methods with std::vector fail to compile

Question

While trying out HippoMocks (Cygwin, GCC 4.5.3, CppUnit) to mock an interface, one of the methods is causing compilation to fail. Further triage shows that only mocking methods with std::vector as arguments would fail.

e.g.

m_Mocks.ExpectCall(m_EmpSvcMock.get(), IEmployeeServiceProxy::GetEmployees); // compile error!
m_Mocks.ExpectCall(m_EmpSvcMock.get(), IEmployeeServiceProxy::AddEmployee); // compile OK!

where

class IEmployeeServiceProxy
{
public:
    virtual ~IEmployeeServiceProxy() { }
    virtual void AddEmployee(const Employee&) = 0;
    virtual void GetEmployees(std::vector<Employee>&) = 0;
};

struct Employee
{
    boost::uuids::uuid Id;
    std::string Name;
};

Compiler error:

/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stream_iterator.h: In member function ‘std::ostream_iterator<_Tp, _CharT, _Traits>& std::ostream_iterator<_Tp, _CharT, _Traits>::operator=(const _Tp&) [with _Tp = EmployeeServiceLib::Employee, _CharT = char, _Traits = std::char_traits<char>, std::ostream_iterator<_Tp, _CharT, _Traits> = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’:
In file included from /usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/iterator:67:0,
                 from /usr/include/boost/uuid/string_generator.hpp:14,
                 from /usr/include/boost/uuid/uuid_generators.hpp:15,
                 from tests/../../RcfTestShared/IEmployeeService.hpp:7,
                 from tests/../IEmployeeServiceProxy.h:11,
                 from tests/ClientTest.h:13,
                 from tests/ClientTest.cpp:8:
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:349:8:   instantiated from ‘static _OI std::__copy_move<false, false, std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II = const EmployeeServiceLib::Employee*, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:404:70:   instantiated from ‘_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false, _II = const EmployeeServiceLib::Employee*, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:442:39:   instantiated from ‘_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false, _II = __gnu_cxx::__normal_iterator<const EmployeeServiceLib::Employee*, std::vector<EmployeeServiceLib::Employee> >, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:474:18:   instantiated from ‘_OI std::copy(_II, _II, _OI) [with _II = __gnu_cxx::__normal_iterator<const EmployeeServiceLib::Employee*, std::vector<EmployeeServiceLib::Employee> >, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
../../RCF/RCF-1.3.1/include/RCF/Tools.hpp:116:9:   instantiated from ‘std::ostream& std::operator<<(std::ostream&, const std::vector<_RealType>&) [with T = EmployeeServiceLib::Employee, std::ostream = std::basic_ostream<char>]’
../../hippomocks/HippoMocks/hippomocks.h:94:5:   instantiated from ‘static void printArg<T>::print(std::ostream&, T, bool) [with T = std::vector<EmployeeServiceLib::Employee>&, std::ostream = std::basic_ostream<char>]’
../../hippomocks/HippoMocks/hippomocks.h:170:5:   instantiated from ‘void ref_tuple<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P>::printTo(std::ostream&) const [with A = std::vector<EmployeeServiceLib::Employee>&, B = NullType, C = NullType, D = NullType, E = NullType, F = NullType, G = NullType, H = NullType, I = NullType, J = NullType, K = NullType, L = NullType, M = NullType, N = NullType, O = NullType, P = NullType, std::ostream = std::basic_ostream<char>]’
tests/ClientTest.cpp:47:1:   instantiated from here
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stream_iterator.h:196:2: error: cannot bind ‘std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >::ostream_type’ lvalue to ‘std::basic_ostream<char>&&’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/ostream:579:5: error:   initializing argument 1 of ‘std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&) [with _CharT = char, _Traits = std::char_traits<char>, _Tp = EmployeeServiceLib::Employee]’

Answer 1

Possibly it's complaining that you don't have operator<< defined for Employee, but I'm not certain. I think you've missed the last line of your error messages? In any case I would read the documentation and see what requirements they have for the class being tested.

Requiring you to define operator== and operator<< and maybe others is pretty standard for a unit testing framework. If you think about it a unit testing framework is going to need to compare objects of the types you are testing and maybe going to try and output those objects when things go wrong.