cleaned up and commented test_multipoll.py

examples/test/test_multipoll.py

 #!/usr/bin/env python
 
-"""TEST"""
+"""
+Test for multipoll.py
+"""
 
 import unittest
 import pexpect
-from collections import defaultdict
-from mininet.log import setLogLevel
 
 class testMultiPoll( unittest.TestCase ):
-    "Test ping with single switch topology (common code)."
 
     def testMultiPoll( self ):
+        "Verify that we receive one ping per second per host"
         p = pexpect.spawn( 'python -m mininet.examples.multipoll' )
-        opts = []
-        opts.append( "\*\*\* (h\d) :" )
-        opts.append( "(h\d+): \d+ bytes from" )
-        opts.append( "Monitoring output for (\d+) seconds" )
-        opts.append( pexpect.EOF )
+        opts = [ "\*\*\* (h\d) :" ,
+                 "(h\d+): \d+ bytes from",
+                 "Monitoring output for (\d+) seconds",
+                 pexpect.EOF ]
         pings = {}
         while True:
             index = p.expect( opts )
@@ -30,11 +29,10 @@ def testMultiPoll( self ):
                 seconds = int( p.match.group( 1 ) )
             else:
                 break
-        self.assertTrue( len(pings) > 0 )
+        self.assertTrue( len( pings ) > 0 )
         # make sure we have received at least one ping per second
         for count in pings.values():
             self.assertTrue( count >= seconds )
 
 if __name__ == '__main__':
-    setLogLevel( 'warning' )
     unittest.main()