phetdam

template <typename Codecvt = std::codecvt_utf8<wchar_t>>
inline std::wstring to_wstring(const std::string& s)
{
  std::wstring_convert<Codecvt> conv;
  return conv.from_bytes(s);
}

phetdam

template <typename T, typename = void>
struct is_size_constructible : std::false_type {};

template <typename T>
struct is_size_constructible<T, std::void_t<typename T::size_type>>
  : std::is_constructible<T, typename T::size_type> {};

template <typename T>
inline constexpr bool is_size_constructible_v = is_size_constructible<T>::value;

phetdam

// `type_triple` specializations to use with TYPED_TEST for MultiTypedTest
using MultiTypedTestTypes = ::testing::Types<
  type_triple<int, double, float>,
  type_triple<char, std::string, size_t>,
  type_triple<std::string, double, void *>
>;
// required macro to set up the typed test suite
TYPED_TEST_SUITE(MultiTypedTest, MultiTypedTestTypes);

phetdam

template <typename T, typename U, typename V>
class func_type_triple {
public:
  using type_a = T;
  using type_b = U;
  using type_c = V;
};

using dat_triple = func_type_triple<int, double, char>;