Function convert

test/operations_test.cpp:60–65

#include <windows.h>

inline std::wstring convert(const char* c)
{
    std::string s(c);

    return std::wstring(s.begin(), s.end());
}

//  Note: these three setenv* functions are not general solutions for the missing
//  setenv* problem on VC++. See Microsoft's _putenv for that need, and ticker #7018