--- a/python/mozbuild/mozbuild/test/configure/common.py
+++ b/python/mozbuild/mozbuild/test/configure/common.py
@@ -165,19 +165,23 @@ class BaseConfigureTest(unittest.TestCas
     def config_sub(self, stdin, args):
         return 0, args[0], ''
 
     def get_sandbox(self, paths, config, args=[], environ={}, mozconfig='',
                     out=None):
         if not out:
             out = StringIO()
 
-        fh, mozconfig_path = tempfile.mkstemp()
-        os.write(fh, mozconfig)
-        os.close(fh)
+        if mozconfig:
+            fh, mozconfig_path = tempfile.mkstemp()
+            os.write(fh, mozconfig)
+            os.close(fh)
+        else:
+            mozconfig_path = os.path.join(os.path.dirname(__file__), 'data',
+                                          'empty_mozconfig')
 
         try:
             environ = dict(
                 environ,
                 OLD_CONFIGURE=os.path.join(topsrcdir, 'old-configure'),
                 MOZCONFIG=mozconfig_path)
 
             paths = dict(paths)
@@ -187,9 +191,10 @@ class BaseConfigureTest(unittest.TestCas
             paths[mozpath.join(autoconf_dir, 'config.sub')] = self.config_sub
 
             sandbox = ConfigureTestSandbox(paths, config, environ,
                                            ['configure'] + args, out, out)
             sandbox.include_file(os.path.join(topsrcdir, 'moz.configure'))
 
             return sandbox
         finally:
-            os.remove(mozconfig_path)
+            if mozconfig:
+                os.remove(mozconfig_path)

new file mode 100644