diff --git a/Lib/distutils/tests/test_build_ext.py b/Lib/distutils/tests/test_build_ext.py
index 93d1881..a1c236a 100644
--- a/Lib/distutils/tests/test_build_ext.py
+++ b/Lib/distutils/tests/test_build_ext.py
@@ -13,11 +13,14 @@
 import unittest
 from test import test_support
 
-
 # http://bugs.python.org/issue4373
 # Don't load the xx module more than once.
 ALREADY_TESTED = False
 
+def _get_source_filename():
+    srcdir = sysconfig.get_config_var('srcdir')
+    return os.path.join(srcdir, 'Modules', 'xxmodule.c')
+
 class BuildExtTestCase(support.TempdirManager,
                        support.LoggingSilencer,
                        unittest.TestCase):
@@ -28,9 +31,7 @@
         self.tmp_dir = tempfile.mkdtemp(prefix="pythontest_")
         self.sys_path = sys.path[:]
         sys.path.append(self.tmp_dir)
-
-        xx_c = os.path.join(sysconfig.project_base, 'Modules', 'xxmodule.c')
-        shutil.copy(xx_c, self.tmp_dir)
+        shutil.copy(_get_source_filename(), self.tmp_dir)
 
     def test_build_ext(self):
         global ALREADY_TESTED
@@ -387,9 +388,11 @@
         self.assertEquals(ext_path, wanted)
 
 def test_suite():
-    if not sysconfig.python_build:
+    src = _get_source_filename()
+    if not os.path.exists(src):
         if test_support.verbose:
-            print 'test_build_ext: The test must be run in a python build dir'
+            print ('test_build_ext: Cannot find source code (test'
+                   ' must run in python build dir)')
         return unittest.TestSuite()
     else: return unittest.makeSuite(BuildExtTestCase)