[gjs: 1/2] gjs-test-utils: Be more liberal in comparing values of different types

[Michael Catanzaro <mcatanzaro src gnome org>]

commit cc51cb9af512571ddcdf569b79bb9fa216eb13af
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue May 18 17:23:40 2021 +0200

    gjs-test-utils: Be more liberal in comparing values of different types
    
    We can safely compare integers of different sizes, assuming they're
    both signed (or unsigned). So assert this instead of requiring two
    arguments of the very same type.

 test/gjs-test-utils.h | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/test/gjs-test-utils.h b/test/gjs-test-utils.h
index 2fe5356a..b641e8cd 100644
--- a/test/gjs-test-utils.h
+++ b/test/gjs-test-utils.h
@@ -13,6 +13,7 @@
 #include <iterator>  // for pair
 #include <limits>    // for numeric_limits
 #include <string>
+#include <type_traits>  // for is_same
 #include <utility>  // IWYU pragma: keep
 
 #include "gjs/context.h"
@@ -44,8 +45,22 @@ namespace Test {
 
 void add_tests_for_toggle_queue();
 
-template <typename T>
-constexpr void assert_equal(T a, T b) {
+template <typename T1, typename T2>
+constexpr bool comparable_types() {
+    if constexpr (std::is_same<T1, T2>()) {
+        return true;
+    } else if constexpr (std::is_arithmetic_v<T1> == std::is_arithmetic_v<T2>) {
+        return std::is_signed_v<T1> == std::is_signed_v<T2>;
+    } else if constexpr (std::is_enum_v<T1> == std::is_enum_v<T2>) {
+        return std::is_signed_v<T1> == std::is_signed_v<T2>;
+    } else {
+        return false;
+    }
+}
+
+template <typename T, typename U>
+constexpr void assert_equal(T a, U b) {
+    static_assert(comparable_types<T, U>());
     if constexpr (std::is_integral_v<T> || std::is_enum_v<T>) {
         if constexpr (std::is_unsigned_v<T>)
             g_assert_cmpuint(a, ==, b);