tests: Integrated ImGui Test Engine

main/gui/include/window.hpp

@@ -13,6 +13,7 @@
 #include <jthread.hpp>
 #include <hex/helpers/opengl.hpp>
 
+struct ImGuiTestEngine;
 struct GLFWwindow;
 struct ImGuiSettingsHandler;
 
@@ -60,6 +61,7 @@ namespace hex {
         void forceNewFrame();
 
         GLFWwindow *m_window = nullptr;
+        ImGuiTestEngine *m_testEngine = nullptr;
 
         std::string m_windowTitle, m_windowTitleFull;