Add missing XCUI core UI tests

tests/Core/UI/CMakeLists.txt

@@ -0,0 +1,30 @@
+# ============================================================
+# UI Core Tests
+# ============================================================
+
+set(UI_TEST_SOURCES
+    test_ui_core.cpp
+)
+
+add_executable(core_ui_tests ${UI_TEST_SOURCES})
+
+if(MSVC)
+    set_target_properties(core_ui_tests PROPERTIES
+        LINK_FLAGS "/NODEFAULTLIB:libcpmt.lib /NODEFAULTLIB:libcmt.lib"
+    )
+endif()
+
+target_link_libraries(core_ui_tests
+    PRIVATE
+    XCEngine
+    GTest::gtest
+    GTest::gtest_main
+)
+
+target_include_directories(core_ui_tests PRIVATE
+    ${CMAKE_SOURCE_DIR}/engine/include
+    ${CMAKE_SOURCE_DIR}/tests/Fixtures
+)
+
+include(GoogleTest)
+gtest_discover_tests(core_ui_tests)