--- a/config/rules.mk
+++ b/config/rules.mk
@@ -1819,44 +1819,46 @@ else
 FWDSLASH_TOPSRCDIR := $(MOZILLA_SRCDIR)
 ifeq ($(HOST_OS_ARCH),WINNT)
 NATIVE_TOPSRCDIR   := $(subst /,\\,$(WIN_TOP_SRC)/mozilla)
 else 
 NATIVE_TOPSRCDIR   := $(MOZILLA_SRCDIR)
 endif
 endif # CYGWIN_WRAPPER
 
+testxpcdir = $(MOZILLA_SRCDIR)/testing/xpcshell
+
 # Test execution
 check::
 	@$(EXIT_ON_ERROR) \
 	for testdir in $(XPCSHELL_TESTS); do \
 	  $(RUN_TEST_PROGRAM) \
-	    $(MOZILLA_SRCDIR)/tools/test-harness/xpcshell-simple/test_all.sh \
+	    $(testxpcdir)/test_all.sh \
 	      $(DIST)/bin/xpcshell \
 	      $(FWDSLASH_TOPSRCDIR) \
 	      $(NATIVE_TOPSRCDIR) \
 	      $(MOZDEPTH)/_tests/xpcshell-simple/$(MODULE)/$$testdir; \
 	done
 
 # Test execution
 check-interactive::
 	@$(EXIT_ON_ERROR) \
 	$(RUN_TEST_PROGRAM) \
-	  $(MOZILLA_SRCDIR)/tools/test-harness/xpcshell-simple/test_one.sh \
+	  $(testxpcdir)/test_one.sh \
 	    $(DIST)/bin/xpcshell \
 	    $(FWDSLASH_TOPSRCDIR) \
 	    $(NATIVE_TOPSRCDIR) \
 	    $(MOZDEPTH)/_tests/xpcshell-simple/$(MODULE)/$$testdir \
 	    $(SOLO_FILE) 1;
 
 # Test execution
 check-one::
 	@$(EXIT_ON_ERROR) \
 	$(RUN_TEST_PROGRAM) \
-	  $(MOZILLA_SRCDIR)/tools/test-harness/xpcshell-simple/test_one.sh \
+	  $(testxpcdir)/test_one.sh \
 	    $(DIST)/bin/xpcshell \
 	    $(FWDSLASH_TOPSRCDIR) \
 	    $(NATIVE_TOPSRCDIR) \
 	    $(MOZDEPTH)/_tests/xpcshell-simple/$(MODULE)/$$testdir \
 	    $(SOLO_FILE) 0;
 
 endif # XPCSHELL_TESTS