Index: test_build_ext.py
===================================================================
--- test_build_ext.py	(revision 64011)
+++ test_build_ext.py	(working copy)
@@ -20,6 +20,8 @@
         sys.path.append(self.tmp_dir)
 
         xx_c = os.path.join(sysconfig.project_base, 'Modules', 'xxmodule.c')
+        if not os.path.isfile(xx_c):
+            xx_c = os.path.join(os.path.dirname(sysconfig.project_base), 'Modules', 'xxmodule.c')
         shutil.copy(xx_c, self.tmp_dir)
 
     def test_build_ext(self):