diff --git a/apps/openmw_test_suite/CMakeLists.txt b/apps/openmw_test_suite/CMakeLists.txt
index 106837a67d..471ae14814 100644
--- a/apps/openmw_test_suite/CMakeLists.txt
+++ b/apps/openmw_test_suite/CMakeLists.txt
@@ -109,8 +109,8 @@ file(DOWNLOAD
 )
 
 target_compile_definitions(openmw_test_suite
-    PRIVATE OPENMW_DATA_DIR="${CMAKE_CURRENT_BINARY_DIR}/data"
-            OPENMW_TEST_SUITE_SOURCE_DIR="${CMAKE_CURRENT_SOURCE_DIR}")
+    PRIVATE OPENMW_DATA_DIR=u8"${CMAKE_CURRENT_BINARY_DIR}/data"
+            OPENMW_TEST_SUITE_SOURCE_DIR=u8"${CMAKE_CURRENT_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/esm3/readerscache.cpp b/apps/openmw_test_suite/esm3/readerscache.cpp
index 826b803b8f..019a18b0b3 100644
--- a/apps/openmw_test_suite/esm3/readerscache.cpp
+++ b/apps/openmw_test_suite/esm3/readerscache.cpp
@@ -39,7 +39,7 @@ namespace
     {
         static constexpr std::size_t sInitialOffset = 324;
         static constexpr std::size_t sSkip = 100;
-        const Files::PathContainer mDataDirs {{std::string(OPENMW_DATA_DIR)}};
+        const Files::PathContainer mDataDirs {{std::filesystem::path{OPENMW_DATA_DIR}}};
         const Files::Collections mFileCollections {mDataDirs, true};
         const std::string mContentFile = "template.omwgame";
         const std::filesystem::path mContentFilePath = mFileCollections.getCollection(".omwgame").getPath(mContentFile);
diff --git a/apps/openmw_test_suite/esmloader/load.cpp b/apps/openmw_test_suite/esmloader/load.cpp
index ea090466a3..b1f3052ac2 100644
--- a/apps/openmw_test_suite/esmloader/load.cpp
+++ b/apps/openmw_test_suite/esmloader/load.cpp
@@ -25,7 +25,7 @@ namespace
 
     struct EsmLoaderTest : Test
     {
-        const Files::PathContainer mDataDirs {{std::string(OPENMW_DATA_DIR)}};
+        const Files::PathContainer mDataDirs {{std::filesystem::path{OPENMW_DATA_DIR}}};
         const Files::Collections mFileCollections {mDataDirs, true};
         const std::vector<std::string> mContentFiles {{"template.omwgame"}};
     };
diff --git a/apps/openmw_test_suite/toutf8/toutf8.cpp b/apps/openmw_test_suite/toutf8/toutf8.cpp
index d1cf6b2851..d34a88e087 100644
--- a/apps/openmw_test_suite/toutf8/toutf8.cpp
+++ b/apps/openmw_test_suite/toutf8/toutf8.cpp
@@ -1,8 +1,10 @@
 #include <components/to_utf8/to_utf8.hpp>
+#include <components/misc/strings/conversion.hpp>
 
 #include <gtest/gtest.h>
 
 #include <fstream>
+#include <filesystem>
 
 #ifndef OPENMW_TEST_SUITE_SOURCE_DIR
 #define OPENMW_TEST_SUITE_SOURCE_DIR ""
@@ -24,7 +26,7 @@ namespace
     {
         std::ifstream file;
         file.exceptions(std::ios::failbit | std::ios::badbit);
-        file.open(std::string(OPENMW_TEST_SUITE_SOURCE_DIR) + "/toutf8/data/" + fileName);
+        file.open(std::filesystem::path{ OPENMW_TEST_SUITE_SOURCE_DIR } / "toutf8" / "data" / Misc::StringUtils::stringToU8String(fileName));
         std::stringstream buffer;
         buffer << file.rdbuf();
         return buffer.str();