使用std::vector的HippoMocks模拟方法无法编译

Question

在尝试使用HippoMocks (Cygwin，GCC 4.5.3，CppUnit)模拟接口时，其中一种方法会导致编译失败。进一步的分类表明，只有使用std::vector作为参数的模拟方法才会失败。

例如：

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

哪里

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;
};

编译器错误：

/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

可能有人抱怨你没有为Employee定义operator<<，但我不确定。我想你遗漏了错误信息的最后一行？在任何情况下，我都会阅读文档，看看他们对要测试的类有什么要求。

对于一个单元测试框架来说，需要你定义operator==和operator<<或者其他的东西是非常标准的。如果你想一想，单元测试框架将需要比较你正在测试的类型的对象，并可能在出现错误时尝试并输出这些对象。