diff --git a/misc/TestUtil.cc b/misc/TestUtil.cc
index 678b61e..e7ef074 100755
--- a/misc/TestUtil.cc
+++ b/misc/TestUtil.cc
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <wchar.h>
 #include <vector>
+#include <string>
 
 #include "../shared/DebugClient.h"
 
@@ -120,3 +121,22 @@ static void cprintf(const wchar_t *fmt, ...) {
     cvprintf(fmt, ap);
     va_end(ap);
 }
+
+std::string narrowString(const std::wstring &input)
+{
+    int mblen = WideCharToMultiByte(
+        CP_UTF8, 0,
+        input.data(), input.size(),
+        NULL, 0, NULL, NULL);
+    if (mblen <= 0) {
+        return std::string();
+    }
+    std::vector<char> tmp(mblen);
+    int mblen2 = WideCharToMultiByte(
+        CP_UTF8, 0,
+        input.data(), input.size(),
+        tmp.data(), tmp.size(),
+        NULL, NULL);
+    assert(mblen2 == mblen);
+    return std::string(tmp.data(), tmp.size());
+}
diff --git a/misc/UnicodeDoubleWidthTest.cc b/misc/UnicodeDoubleWidthTest.cc
index fd850e5..4f1d059 100644
--- a/misc/UnicodeDoubleWidthTest.cc
+++ b/misc/UnicodeDoubleWidthTest.cc
@@ -88,7 +88,7 @@ int main(int argc, char *argv[]) {
     for (int px = 1; px < 50; ++px) {
         setFont(kFaceName, px);
         if (!performTest()) {
-            trace("FAILURE: %ls %dpx", kFaceName, px);
+            trace("FAILURE: %s %dpx", narrowString(kFaceName).c_str(), px);
         }
     }
     trace("Test complete");