Fix test_config.h to include real engines found

Instead of hardcoding them by architecture, create the right
list of engines from the support found by CMake.

Signed-off-by: Jose Luis Rivero <jrivero@honurobotics.com>

test/test_config.h.in

@@ -9,16 +9,33 @@
 #define RENDER_ENGINE_VALUES ::testing::ValuesIn(\
     gz::rendering::TestValues())
 
+#include <vector>
+#include <gz/common/Util.hh>
+#include <gz/rendering/config.hh>
+
 /// \todo(anyone) re-enable ogre2 test once ogre 2.2 works on macOS
 #ifdef __APPLE__
 static const std::vector<const char *> kRenderEngineTestValues{"ogre", "optix"};
 #else
-static const std::vector<const char *> kRenderEngineTestValues{"ogre2", "optix"};
+  #if defined(HAVE_OGRE) && defined(HAVE_OPTIX) && defined(HAVE_OGRE2)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre", "ogre2", "optix"};
+  #elif defined(HAVE_OGRE) && defined(HAVE_OPTIX)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre", "optix"};
+  #elif defined(HAVE_OGRE) && defined(HAVE_OGRE2)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre", "ogre2"};
+  #elif defined(HAVE_OGRE2) && defined(HAVE_OPTIX)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre2", "optix"};
+  #elif defined(HAVE_OGRE)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre"};
+  #elif defined(HAVE_OGRE2)
+  static const std::vector<const char *> kRenderEngineTestValues{"ogre2"};
+  #elif defined(HAVE_OPTIX)
+  static const std::vector<const char *> kRenderEngineTestValues{"optix"};
+  #else
+  #warning "Can not detect a rendering engine support: ogre | ogre2 | optix"
+  #endif
 #endif
 
-#include <vector>
-#include <gz/common/Util.hh>
-
 namespace ignition
 {
   namespace rendering