Had to rename sfml to sfmlbackend because on Windows the filesystem is case insensitive so include <SFML/*> was accidentally including _my_ <sfml/config.hpp> file.

tests/shaders.cpp

@@ -1,7 +1,7 @@
 #include <catch2/catch_test_macros.hpp>
 #include <fmt/core.h>
 #include <string>
-#include "sfml/shaders.hpp"
+#include "sfmlbackend/shaders.hpp"
 
 using namespace fmt;
 

tests/sound.cpp

@@ -1,7 +1,7 @@
 #include <catch2/catch_test_macros.hpp>
 #include <fmt/core.h>
 #include <string>
-#include "sfml/sound.hpp"
+#include "sfmlbackend/sound.hpp"
 
 using namespace fmt;
 

tests/textures.cpp

@@ -1,7 +1,7 @@
 #include <catch2/catch_test_macros.hpp>
 #include <fmt/core.h>
 #include <string>
-#include "sfml/textures.hpp"
+#include "sfmlbackend/textures.hpp"
 
 using namespace fmt;