diff --git a/mozilla/xpcom/glue/nsTArray.h b/mozilla/xpcom/glue/nsTArray.h
index 0d9c75cafdb..0b366148a35 100644
--- a/mozilla/xpcom/glue/nsTArray.h
+++ b/mozilla/xpcom/glue/nsTArray.h
@@ -78,7 +78,7 @@ class NS_COM_GLUE nsTArray_base {
       return mHdr->mCapacity;
     }
 
-#if defined(DEBUG) || defined(ENABLE_TESTS)
+#ifdef DEBUG
     void* DebugGetHeader() {
       return mHdr;
     }
diff --git a/mozilla/xpcom/tests/TestTArray.cpp b/mozilla/xpcom/tests/TestTArray.cpp
index 44ccac9df3f..702ded93318 100644
--- a/mozilla/xpcom/tests/TestTArray.cpp
+++ b/mozilla/xpcom/tests/TestTArray.cpp
@@ -410,6 +410,9 @@ static PRBool test_ptrarray() {
 
 //----
 
+// This test relies too heavily on the existance of DebugGetHeader to be
+// useful in non-debug builds.
+#ifdef DEBUG
 static PRBool test_autoarray() {
   PRUint32 data[] = {4,6,8,2,4,1,5,7,3};
   nsAutoTArray<PRUint32, NS_ARRAY_LENGTH(data)> array;
@@ -473,6 +476,7 @@ static PRBool test_autoarray() {
 
   return PR_TRUE;
 }
+#endif
 
 //----
 
@@ -492,7 +496,9 @@ static const struct Test {
   DECL_TEST(test_comptr_array),
   DECL_TEST(test_refptr_array),
   DECL_TEST(test_ptrarray),
+#ifdef DEBUG
   DECL_TEST(test_autoarray),
+#endif
   { nsnull, nsnull }
 };