diff --git a/apps/openmw_test_suite/CMakeLists.txt b/apps/openmw_test_suite/CMakeLists.txt
index 34892905c1..7af6520f35 100644
--- a/apps/openmw_test_suite/CMakeLists.txt
+++ b/apps/openmw_test_suite/CMakeLists.txt
@@ -115,7 +115,7 @@ file(DOWNLOAD
 
 target_compile_definitions(openmw_test_suite
     PRIVATE OPENMW_DATA_DIR=u8"${CMAKE_CURRENT_BINARY_DIR}/data"
-            OPENMW_TEST_SUITE_SOURCE_DIR=u8"${CMAKE_CURRENT_SOURCE_DIR}")
+            OPENMW_PROJECT_SOURCE_DIR=u8"${PROJECT_SOURCE_DIR}")
 
 if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.16 AND MSVC)
     target_precompile_headers(openmw_test_suite PRIVATE
diff --git a/apps/openmw_test_suite/toutf8/toutf8.cpp b/apps/openmw_test_suite/toutf8/toutf8.cpp
index 202c0e4890..f189294cf2 100644
--- a/apps/openmw_test_suite/toutf8/toutf8.cpp
+++ b/apps/openmw_test_suite/toutf8/toutf8.cpp
@@ -6,8 +6,8 @@
 #include <filesystem>
 #include <fstream>
 
-#ifndef OPENMW_TEST_SUITE_SOURCE_DIR
-#define OPENMW_TEST_SUITE_SOURCE_DIR ""
+#ifndef OPENMW_PROJECT_SOURCE_DIR
+#define OPENMW_PROJECT_SOURCE_DIR "."
 #endif
 
 namespace
@@ -26,7 +26,7 @@ namespace
     {
         std::ifstream file;
         file.exceptions(std::ios::failbit | std::ios::badbit);
-        file.open(std::filesystem::path{ OPENMW_TEST_SUITE_SOURCE_DIR } / "toutf8" / "data"
+        file.open(std::filesystem::path{ OPENMW_PROJECT_SOURCE_DIR } / "apps" / "openmw_test_suite" / "toutf8" / "data"
             / Misc::StringUtils::stringToU8String(fileName));
         std::stringstream buffer;
         buffer << file.rdbuf();