test: Add test for traits

Author: FrozenLemonTee

tests/basic/test_templates.cpp

@@ -1,12 +1,112 @@
 #include <gtest/gtest.h>
 
-import mcpplibs.templates;
+import mcpplibs.primitive;
 
-TEST(TemplatesTest, HelloMcpp) {
-  testing::internal::CaptureStdout();
-  mcpplibs::templates::hello_mcpp();
-  std::string output = testing::internal::GetCapturedStdout();
-  EXPECT_EQ(output, "hello mcpp!\n");
+namespace {
+
+struct UserInteger {
+  int value;
+};
+
+struct NotRegistered {
+  int value;
+};
+
+struct BadRep {
+  int value;
+};
+
+struct BadKind {
+  int value;
+};
+
+} // namespace
+
+template <>
+struct mcpplibs::primitive::underlying::traits<UserInteger> {
+  using value_type = UserInteger;
+  using rep_type = int;
+
+  static constexpr bool enabled = true;
+  static constexpr auto kind = mcpplibs::primitive::underlying::category::integer;
+
+  static constexpr rep_type to_rep(value_type value) noexcept { return value.value; }
+
+  static constexpr value_type from_rep(rep_type value) noexcept { return UserInteger{value}; }
+
+  static constexpr bool is_valid_rep(rep_type) noexcept { return true; }
+};
+
+template <>
+struct mcpplibs::primitive::underlying::traits<BadRep> {
+  using value_type = BadRep;
+  using rep_type = BadRep;
+
+  static constexpr bool enabled = true;
+  static constexpr auto kind = mcpplibs::primitive::underlying::category::integer;
+
+  static constexpr rep_type to_rep(value_type value) noexcept { return value; }
+
+  static constexpr value_type from_rep(rep_type value) noexcept { return value; }
+
+  static constexpr bool is_valid_rep(rep_type) noexcept { return true; }
+};
+
+template <>
+struct mcpplibs::primitive::underlying::traits<BadKind> {
+  using value_type = BadKind;
+  using rep_type = int;
+
+  static constexpr bool enabled = true;
+  static constexpr auto kind = mcpplibs::primitive::underlying::category::floating;
+
+  static constexpr rep_type to_rep(value_type value) noexcept { return value.value; }
+
+  static constexpr value_type from_rep(rep_type value) noexcept { return BadKind{value}; }
+
+  static constexpr bool is_valid_rep(rep_type) noexcept { return true; }
+};
+
+TEST(PrimitiveTraitsTest, StandardTypeConcepts) {
+  EXPECT_TRUE((mcpplibs::primitive::std_integer<int>));
+  EXPECT_TRUE((mcpplibs::primitive::std_integer<long long>));
+  EXPECT_FALSE((mcpplibs::primitive::std_integer<bool>));
+  EXPECT_FALSE((mcpplibs::primitive::std_integer<char>));
+
+  EXPECT_TRUE((mcpplibs::primitive::std_floating<float>));
+  EXPECT_TRUE((mcpplibs::primitive::std_floating<double>));
+  EXPECT_TRUE((mcpplibs::primitive::std_floating<long double>));
+
+  EXPECT_TRUE((mcpplibs::primitive::std_bool<bool>));
+  EXPECT_FALSE((mcpplibs::primitive::std_bool<int>));
+
+  EXPECT_TRUE((mcpplibs::primitive::std_char<char>));
+  EXPECT_TRUE((mcpplibs::primitive::std_char<char8_t>));
+  EXPECT_TRUE((mcpplibs::primitive::std_char<wchar_t>));
+
+  EXPECT_TRUE((mcpplibs::primitive::std_underlying_type<int>));
+  EXPECT_TRUE((mcpplibs::primitive::std_underlying_type<double>));
+  EXPECT_FALSE((mcpplibs::primitive::std_underlying_type<void*>));
+}
+
+TEST(PrimitiveTraitsTest, UnderlyingTraitsDefaultsAndCustomRegistration) {
+  EXPECT_TRUE((mcpplibs::primitive::underlying_type<int>));
+  EXPECT_EQ(mcpplibs::primitive::underlying::traits<int>::kind,
+            mcpplibs::primitive::underlying::category::integer);
+
+  EXPECT_TRUE((mcpplibs::primitive::underlying_type<UserInteger>));
+  EXPECT_EQ(mcpplibs::primitive::underlying::traits<UserInteger>::to_rep(UserInteger{7}), 7);
+
+  EXPECT_FALSE((mcpplibs::primitive::underlying_type<NotRegistered>));
+  EXPECT_FALSE((mcpplibs::primitive::underlying::traits<NotRegistered>::enabled));
+}
+
+TEST(PrimitiveTraitsTest, UnderlyingTypeRequiresValidRepTypeAndCategoryConsistency) {
+  EXPECT_TRUE((mcpplibs::primitive::underlying::traits<BadRep>::enabled));
+  EXPECT_FALSE((mcpplibs::primitive::underlying_type<BadRep>));
+
+  EXPECT_TRUE((mcpplibs::primitive::underlying::traits<BadKind>::enabled));
+  EXPECT_FALSE((mcpplibs::primitive::underlying_type<BadKind>));
 }
 
 int main(int argc, char **argv) {