diff --git a/xpcom/tests/TestXPIDLString.cpp b/xpcom/tests/gtest/TestXPIDLString.cpp
similarity index 73%
rename from xpcom/tests/TestXPIDLString.cpp
rename to xpcom/tests/gtest/TestXPIDLString.cpp
index d85cdd56fe6d..94e794d5716d 100644
--- a/xpcom/tests/TestXPIDLString.cpp
+++ b/xpcom/tests/gtest/TestXPIDLString.cpp
@@ -1,6 +1,7 @@
 #include "nsString.h"
 #include "nsReadableUtils.h"
 #include "nsXPIDLString.h"
+#include "gtest/gtest.h"
 
 static void
 nsXPIDLStringTest_Value(char16_t** aResult)
@@ -8,11 +9,10 @@ nsXPIDLStringTest_Value(char16_t** aResult)
     *aResult = ToNewUnicode(NS_LITERAL_STRING("Hello, World"));
 }
 
-int
-main(int argc, char* argv[])
+TEST(XPIDLString, Main)
 {
     nsXPIDLString s1;
     nsXPIDLStringTest_Value(getter_Copies(s1));
-    return 0;
+    EXPECT_TRUE(s1.EqualsLiteral("Hello, World"));
 }
 
diff --git a/xpcom/tests/gtest/moz.build b/xpcom/tests/gtest/moz.build
index 4a04a2be0c16..54bf5ab3ea54 100644
--- a/xpcom/tests/gtest/moz.build
+++ b/xpcom/tests/gtest/moz.build
@@ -20,6 +20,7 @@ UNIFIED_SOURCES += [
     'TestThreadPool.cpp',
     'TestTimeStamp.cpp',
     'TestUTF.cpp',
+    'TestXPIDLString.cpp',
 ]
 
 FINAL_LIBRARY = 'xul-gtest'
diff --git a/xpcom/tests/moz.build b/xpcom/tests/moz.build
index 6d97acccccf8..28dff1b61cf5 100644
--- a/xpcom/tests/moz.build
+++ b/xpcom/tests/moz.build
@@ -81,7 +81,6 @@ if CONFIG['MOZ_MEMORY']:
 # XXX Make these tests work in libxul builds.
 #CPP_UNIT_TESTS += [
 #    'TestThreads',
-#    'TestXPIDLString',
 #    'TestAtoms',
 #]