adding sanity check for cluster edition

examples/test/test_clusterSanity.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+
+'''
+A simple sanity check test for cluster edition
+'''
+
+import unittest
+import pexpect
+
+class clusterSanityCheck( unittest.TestCase ):
+
+    prompt = 'mininet>'
+
+    def testClusterPingAll( self ):
+        p = pexpect.spawn( 'python -m mininet.examples.clusterSanity' )
+        p.expect( self.prompt )
+        p.sendline( 'pingall' )
+        p.expect ( '(\d+)% dropped' )
+        percent = int( p.match.group( 1 ) ) if p.match else -1
+        self.assertEqual( percent, 0 )
+        p.expect( self.prompt )
+        p.sendline( 'exit' )
+        p.wait()
+
+
+if __name__  == '__main__':
+    unittest.main()