diff --git a/xpcom/tests/windows/makefile.win b/xpcom/tests/windows/makefile.win
index ad8833fa91c4..f1b47ae4c76e 100644
--- a/xpcom/tests/windows/makefile.win
+++ b/xpcom/tests/windows/makefile.win
@@ -26,7 +26,8 @@ MAKE_OBJ_TYPE	= EXE
 
 PROG1 = .\$(OBJDIR)\TestCOM.exe
 PROG2 = .\$(OBJDIR)\TestHelloXPLoop.exe
-PROGRAMS = $(PROG1) $(PROG2)
+PROG3 = .\$(OBJDIR)\nsStringTest.exe
+PROGRAMS = $(PROG1) $(PROG2) $(PROG3)
 
 LINCS=-I$(PUBLIC)\xpcom
 
@@ -46,3 +47,5 @@ clobber::
 
 $(PROG1): $(OBJDIR) TestCOM.cpp
 $(PROG2): $(OBJDIR) TestHelloXPLoop.cpp
+$(PROG2): $(OBJDIR) nsStringTest.cpp
+
diff --git a/xpcom/tests/windows/nsStringTest.cpp b/xpcom/tests/windows/nsStringTest.cpp
new file mode 100644
index 000000000000..3a156b3fa99d
--- /dev/null
+++ b/xpcom/tests/windows/nsStringTest.cpp
@@ -0,0 +1,32 @@
+
+#include <iostream.h>
+#include "nsStr.h"
+#include "nsStringTest2.h"
+#include "nsString.h"
+
+int main(){
+
+  nsString temp("\t\t\n\r\n\r25,* \t   \n\n \t");
+  temp.CompressWhitespace();
+
+  nsString temp1("\t\t\n\r\n\r25,* \t   \n\n \t");
+  temp1.CompressSet("\t\n\r ",' ',false,false);
+
+  nsString temp3("");
+  char* s=temp3.ToNewCString();
+  delete s;
+
+  char* f=nsAutoString("").ToNewCString();
+  char* f1=nsCAutoString("").ToNewCString();
+  delete f;
+  delete f1;
+  
+
+  CStringTester gStringTester;
+
+  gStringTester.TestI18nString();
+
+  return 0;
+}
+
+
diff --git a/xpcom/tests/windows/nsStringTest2.h b/xpcom/tests/windows/nsStringTest2.h
new file mode 100644
index 000000000000..16ffc11a7e09
--- /dev/null
+++ b/xpcom/tests/windows/nsStringTest2.h
@@ -0,0 +1,444 @@
+/********************************************************************************************
+ *
+ * MODULES NOTES:
+ *
+ *  This file is designed to help test the new nsString classes.
+ * 
+ * Contributor(s):
+ *   Rick Gessner <rickg@netscape.com>
+ * 
+ * History:
+ *
+ *  02.29.2000: Original files (rickg)
+ *  03.02.2000: Flesh out the interface to be compatible with old library (rickg)
+ *  
+ ********************************************************************************************/
+
+#ifndef _STRINGTEST2
+#define _STRINGTEST2
+
+
+#include "nsString.h"
+#include <time.h>
+
+#define USE_STL 
+
+#ifdef USE_STL
+#include <string>
+using namespace std;
+#endif
+
+#define USE_WIDE  1
+#ifdef  USE_WIDE
+  #define stringtype  nsString
+  #define astringtype nsAutoString
+  #define chartype    PRUnichar
+#else
+  #define stringtype  nsCString
+  #define astringtype nsCAutoString
+  #define chartype    char
+#endif
+
+#include <stdio.h>
+const double gTicks = 1.0e-7;
+
+
+
+
+
+/********************************************************
+  
+    This class's only purpose in life is to test the 
+    netscape string library. We exercise the string
+    API's here, and do a bit of performance testing
+    against the standard c++ library string (from STL).
+
+ ********************************************************/
+class CStringTester {
+
+public:
+
+	int TestI18nString();
+    
+};
+
+
+
+
+//test 1: unicode char is stripped correctly using StripChars()
+void nsStringTest1(){
+	PRUnichar test[]={0x0041,0x0051,0x0052,0x0000};
+	nsString T(test);
+	PRUnichar result[]={0x0051,0x0052,0x0000};
+	nsString R(result);
+	T.StripChars("ABC");
+	NS_ASSERTION(T.Equals(R), "Test 1: Unicode comparison error");
+}
+//test 2: unicode char is not matched and stripped when high-order byte is not 0x00
+void nsStringTest2(){
+	PRUnichar test[]={0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[]={0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.StripChars("ABC");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+	//test 3: unicode char is not matched and stripped when high-order byte is 0xFF
+void nsStringTest3(){
+
+	PRUnichar test[] =  {0xFF41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0xFF41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(test);
+	T.StripChars("ABC");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest4(){
+	//test 4: unicode char is matched and stripped correctly using StripChar()
+	PRUnichar test[] =  {0x0041,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] = {0x0051,0x0052,0x0000};
+	nsAutoString R(result);
+	T.StripChar('A');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest5(){
+	//test 5: unicode char is not matched and stripped when high-order byte is not 0x00
+
+	PRUnichar test[]={0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[]={0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.StripChar('A');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest6(){
+	//test 6: unicode char is not matched and stripped when high-order byte is 0xFF
+
+	PRUnichar test[] =  {0xFF41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0xFF41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.StripChar('A');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest7(){
+	//test 7: unicode char is matched and replaced correctly using ReplaceChar()
+	
+	PRUnichar test[] =  {0x0041,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] = {0x0050,0x0051,0x0052,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar('A',0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest8(){
+	//test 8: unicode char is not matched or replaced when high-order byte != 0x00
+	
+	PRUnichar test[] =  {0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar('A',0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest9(){
+	//test 9: unicode char is not matched or replaced when high-order byte matches search char
+	
+	PRUnichar test[] =  {0x4150,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4150,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar('A',0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest10(){
+	//test 10: unicode char is not matched or replaced when high-order byte == 0xFF
+	
+	PRUnichar test[] =  {0xFFc1,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0xFFc1,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar('A',0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+
+void nsStringTest11(){
+	//test 11: unicode char is correctly replaced when parameter 1 is a string
+	
+	PRUnichar test[] =  {0x0041,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] = {0x0050,0x0051,0x0052,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar("ABC",0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest12(){
+	//test 12: unicode char is not replaced when high-order byte != 0x00
+	
+	PRUnichar test[] =  {0x4e41,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4e41,0x0051,0x0052,0x0000};
+	nsAutoString R(result);
+ 	T.ReplaceChar("ABC",0x50);
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+
+}
+void nsStringTest13(){
+	//test 13: unicode char is not replaced when high-order byte matches char in search string
+	PRUnichar test[] =  {0x4150,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4150,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar("ABC",'T');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+
+}
+void nsStringTest14(){
+	PRUnichar test[] =  {0xFFc2,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0xFFc2,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.ReplaceChar("ABC",'T');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest15(){
+	PRUnichar test[] =  {0xFFc2,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0xFFc2,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+ 	PRUnichar s = 0xc2; //compiler error on this line
+	T.ReplaceChar(s,'T');
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+
+void nsStringTest16(){
+	/* TESTS for ReplaceSubstring()*/
+	
+	PRUnichar test[] =  {0x0041,0x0042,0x0043,0x0044,0x0045,0x0000};
+	nsAutoString T(test);
+    PRUnichar result[] = {0x0044,0x0045,0x0046,0x0044,0x0045};
+	nsAutoString R(result);
+	T.ReplaceSubstring("ABC","DEF");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+
+}
+void nsStringTest17(){
+
+	PRUnichar test[] =  {0x0041,0x4e42,0x0043,0x0044,0x0045,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x0041,0x4e42,0x0043,0x0044,0x0045,0x0000};
+	nsAutoString R(result);
+	T.ReplaceSubstring("ABC","DEF");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest18(){
+	 /*TESTS for Trim()*/
+
+ 	PRUnichar test[] =  {0x0041,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+    PRUnichar result[] = {0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R (result);
+	T.Trim("ABC");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest19(){
+	PRUnichar test[] =  {0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4e41,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString R(result);
+	T.Trim("ABC");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+}
+void nsStringTest22(){
+	PRUnichar test[] =  {0x4e51,0x4e52,0x4e53,0x4e41,0x0000};
+	nsAutoString T(test);
+	PRUnichar result[] =  {0x4e51,0x4e52,0x4e53,0x4e41,0x0000};
+	nsAutoString R(result);
+	T.Trim("ABC");
+	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+
+}
+//void nsStringTest23(){
+//	PRUnichar test[] =  {0x4e51,0x4e52,0x4e53,0x4e22,0x0000};
+//	nsAutoString T(test);
+// 	PRUnichar s(0x4e22);
+//	PRUnichar result[] =  {0x4e51,0x4e52,0x4e53,0x0000};
+//	nsAutoString R(result);
+//	T.Trim(s,PR_TRUE,PR_TRUE,PR_FALSE);
+//	NS_ASSERTION(T.Equals(R), "Unicode comparison error");
+//}
+void nsStringTest24(){
+	/*TESTS for Find()*/
+	PRUnichar test[] =  {0x0041,0x0042,0x0043,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.Find("ABC") == 0, "Unicode comparison error");
+
+}
+void nsStringTest25(){
+	PRUnichar test[] =  {0x4e41,0x4e42,0x4e43,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.Find("ABC") == -1, "Unicode comparison error");
+
+}
+void nsStringTest26(){
+	PRUnichar test[] =  {0xFFc1,0x0051,0x0052,0x0053,0x0000};
+	nsAutoString T(test);
+ 	PRUnichar str[] = {0xc1,0x51,0x52};
+	nsAutoString S(str);
+	NS_ASSERTION(T.Find(S) == -1, "Unicode comparison error");
+}
+void nsStringTest27(){
+    /*TESTS for FindChar()*/
+  
+	PRUnichar test[] =  {0x0041,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindChar('A') == 0, "Unicode comparison error");
+}
+void nsStringTest28(){
+	PRUnichar test[] =  {0x4e41,0x4e42,0x4e43,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindChar('A') == -1, "Unicode comparison error");
+}
+void nsStringTest29(){
+	PRUnichar test[] =  {0xFFc1,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindChar(0xc1) == -1, "Unicode comparison error");
+
+}
+void nsStringTest30(){
+	PRUnichar test[] =  {0x4132,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindChar('A1') == -1, "Unicode comparison error");
+}
+	/*TESTS for FindCharInSet()*/
+void nsStringTest31(){
+	PRUnichar test[] =  {0x0041,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindCharInSet("ABC") == 0, "Unicode comparison error");
+}
+void nsStringTest32(){
+	PRUnichar test[] =  {0x4e41,0x4e42,0x4e43,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindCharInSet("ABC") == -1, "Unicode comparison error");
+	
+}
+void nsStringTest33(){
+	PRUnichar test[] =  {0xFFc1,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+ 	PRUnichar str[] = {0xc1,0x51,0x52};
+	nsAutoString s(str);
+	NS_ASSERTION(T.FindCharInSet(s) == -1, "Unicode comparison error");
+}
+void nsStringTest34(){
+	PRUnichar test[] =  {0x4132,0x5132,0x5232,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.FindCharInSet("ABC") == -1, "Unicode comparison error");
+}
+	/*TESTS for RFind()*/
+void nsStringTest35(){
+
+	PRUnichar test[] =  {0x0051,0x0052,0x0041,0x0042,0x0043,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.RFind("ABC") == 2, "Unicode comparison error");
+}
+void nsStringTest36(){
+	PRUnichar test[] =  {0x4e41,0x4e42,0x4e43,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.RFind("ABC") == -1, "Unicode comparison error");
+}
+void nsStringTest37(){
+	PRUnichar test[] =  {0xFFc1,0xFFc2,0xFFc3,0x4e53,0x0000};
+	nsAutoString T(test);
+ 	PRUnichar str[] = {0xc1,0xc2,0xc3};
+	nsAutoString s(str);	
+	NS_ASSERTION(T.RFind(s) == -1, "Unicode comparison error");
+}
+	/*TESTS for RFindCharInSet*/
+void nsStringTest38(){
+
+ 	PRUnichar test[] =  {0x0041,0x0042,0x0043,0x0000};
+	nsAutoString T(test);
+	int res = T.RFindCharInSet("ABC");
+	NS_ASSERTION(res==0, "Unicode comparison error");
+}
+void nsStringTest39(){
+ 	PRUnichar test[] =  {0x4e41,0x4e42,0x4e43,0x4e53,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.RFindCharInSet("ABC") == -1, "Unicode comparison error");
+}
+void nsStringTest40(){
+ 	PRUnichar test[] =  {0xFFc1,0x4e51,0x4e52,0x4e53,0x0000};
+	nsAutoString T(test);
+ 	PRUnichar str[] = {0xc1,0xc2,0xc3};
+	nsAutoString s(str);	
+	NS_ASSERTION(T.RFindCharInSet(s) == -1, "Unicode comparison error");
+}
+void nsStringTest41(){
+ 	PRUnichar test[] =  {0x4132,0x0051,0x0052,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.RFindCharInSet("ABC") == -1, "Unicode comparison error");
+}
+	/*  TESTS for Compare() */
+void nsStringTest42(){
+ 	PRUnichar test[] =  {0x0041,0x0042,0x0043,0x0000};
+	nsAutoString T(test);
+	NS_ASSERTION(T.Compare("ABC") == 0, "Unicode comparison error");
+}				   
+void nsStringTest43(){
+ 	PRUnichar test[] =  {0xc341,0xc342,0xc343};
+	nsAutoString T(test);
+	NS_ASSERTION(T.Compare("ABC") == 1, "Unicode comparison error");
+}
+
+
+int CStringTester::TestI18nString(){
+	nsStringTest1();
+	nsStringTest2();
+	nsStringTest3();
+	nsStringTest4();
+	nsStringTest5();
+	nsStringTest6();
+	nsStringTest7();
+	nsStringTest8();
+	nsStringTest9();
+	nsStringTest10();
+	nsStringTest11();
+	nsStringTest12();
+	nsStringTest13();
+	nsStringTest14();
+	nsStringTest15();
+	nsStringTest16();
+	nsStringTest17();
+	nsStringTest18();
+	nsStringTest19();
+	//nsStringTest20();
+	//nsStringTest21();
+	nsStringTest22();
+	//nsStringTest23();
+	nsStringTest24();
+   	nsStringTest25();
+	nsStringTest26();
+	nsStringTest27();
+	nsStringTest28();
+	nsStringTest29();
+	nsStringTest30();
+	nsStringTest31();
+	nsStringTest32();
+	nsStringTest33();
+	nsStringTest34();
+	nsStringTest35();
+	nsStringTest36();
+	nsStringTest37();
+	nsStringTest38();
+	nsStringTest39();
+	nsStringTest40();
+	nsStringTest41();
+	nsStringTest42();
+	nsStringTest43();
+
+	return 0;
+}
+
+#endif
+