Improve error message for manufacturer test

Author: AntoinePrv

include/xsimd/config/xsimd_cpu_features_x86.hpp

@@ -266,6 +266,33 @@ namespace xsimd
         return x86_manufacturer::unknown;
     };
 
+    /** Return a string representation of an @ref x86_manufacturer value. */
+    constexpr const char* x86_manufacturer_name(x86_manufacturer m) noexcept
+    {
+        switch (m)
+        {
+        case x86_manufacturer::intel:
+            return "intel";
+        case x86_manufacturer::amd:
+            return "amd";
+        case x86_manufacturer::via:
+            return "via";
+        case x86_manufacturer::zhaoxin:
+            return "zhaoxin";
+        case x86_manufacturer::hygon:
+            return "hygon";
+        case x86_manufacturer::transmeta:
+            return "transmeta";
+        case x86_manufacturer::elbrus:
+            return "elbrus";
+        case x86_manufacturer::microsoft_vpc:
+            return "microsoft_vpc";
+        case x86_manufacturer::unknown:
+            return "unknown";
+        }
+        return "invalid";
+    }
+
     struct x86_cpuid_leaf1_traits
     {
         static constexpr detail::x86_reg32_t leaf = 1;

test/test_cpu_features.cpp

@@ -109,7 +109,8 @@ TEST_CASE("[cpu_features] x86 manufacturer from environment")
         bool match = std::any_of(manufacturers.begin(), manufacturers.end(), [&](const entry& e)
                                  { return e.value == manufacturer && detail::contains(allowed, e.name); });
 
-        auto const msg = std::string("XSIMD_TEST_CPU_ASSUME_MANUFACTURER = ") + val;
+        auto const msg = std::string("XSIMD_TEST_CPU_ASSUME_MANUFACTURER = ") + val
+            + ", actual = " + xsimd::x86_manufacturer_name(manufacturer);
         INFO(msg);
         CHECK_UNARY(match);
     }