--- a/tests/hghave	Fri Jun 08 15:11:05 2012 +0200
+++ b/tests/hghave	Sun May 27 18:25:04 2012 +0200
@@ -202,7 +202,7 @@
         os.rmdir(d)
 
 def has_pyflakes():
-    return matchoutput('echo "import re" 2>&1 | pyflakes',
+    return matchoutput("sh -c \"echo 'import re' 2>&1 | pyflakes\"",
                        r"<stdin>:1: 're' imported but unused",
                        True)