cleaned up and commented test_popen.py

examples/test/test_popen.py

 #!/usr/bin/env python
 
-"""TEST"""
+"""
+Test for popen.py and popenpoll.py
+"""
 
 import unittest
 import pexpect
-from collections import defaultdict
-from mininet.log import setLogLevel
 
 class testPopen( unittest.TestCase ):
-    "Test ping with single switch topology (common code)."
 
     def pingTest( self, name ):
+        "Verify that there are no dropped packets for each host"
         p = pexpect.spawn( 'python -m %s' % name )
-        opts = []
-        opts.append( "<(h\d+)>: PING " )
-        opts.append( "<(h\d+)>: (\d+) packets transmitted, (\d+) received" )
-        opts.append( pexpect.EOF )
+        opts = [ "<(h\d+)>: PING ",
+                 "<(h\d+)>: (\d+) packets transmitted, (\d+) received",
+                 pexpect.EOF ]
         pings = {}
         while True:
             index = p.expect( opts )
@@ -26,11 +25,13 @@ def pingTest( self, name ):
                 name = p.match.group(1)
                 transmitted = p.match.group(2)
                 received = p.match.group(3)
+                # verify no dropped packets
                 self.assertEqual( received, transmitted )
                 pings[ name ] += 1
             else:
                 break
         self.assertTrue( len(pings) > 0 )
+        # verify that each host has gotten results
         for count in pings.values():
             self.assertEqual( count, 1 )
 
@@ -38,8 +39,7 @@ def testPopen( self ):
         self.pingTest( 'mininet.examples.popen' )
 
     def testPopenPoll( self ):
-        self.pingTest( 'mininet.examples.popenpoll')
+        self.pingTest( 'mininet.examples.popenpoll' )
 
 if __name__ == '__main__':
-    setLogLevel( 'warning' )
     unittest.main()