test: rework lib stuff to share common files

test/lib/locator/shared/main.cpp

@@ -0,0 +1,24 @@
+#include <gtest/gtest.h>
+#include <entt/core/attribute.h>
+#include <entt/locator/locator.hpp>
+#include "types.h"
+
+ENTT_API void set_up(const entt::locator<service>::node_type &);
+ENTT_API void use_service(int);
+
+TEST(Lib, Locator) {
+    entt::locator<service>::emplace().value = 42;
+
+    ASSERT_EQ(entt::locator<service>::value().value, 42);
+
+    set_up(entt::locator<service>::handle());
+    use_service(3);
+
+    ASSERT_EQ(entt::locator<service>::value().value, 3);
+
+    // service updates do not propagate across boundaries
+    entt::locator<service>::emplace().value = 42;
+    use_service(3);
+
+    ASSERT_EQ(entt::locator<service>::value().value, 42);
+}