Create test_switchdpidassignment.py

Regression tests to verify switch datapath ID assignment.

mininet/test/test_switchdpidassignment.py

+#!/usr/bin/env python
+
+"""Package: mininet
+   Regression tests for switch dpid assignment."""
+
+import unittest
+import re
+
+from mininet.net import Mininet
+from mininet.node import Switch
+from mininet.topo import Topo
+from mininet.log import setLogLevel
+
+class testSwitchDpidAssignment ( unittest.TestCase ):
+    """Verify Switch dpid assignment."""
+
+    def testDefaultDpid ( self ):
+        """Verify that the default dpid is assigned using a valid provided
+        canonical switchname if no dpid is passed in switch creation."""
+        mn = Mininet( Topo() )
+        switch = mn.addSwitch( 's1' )
+        self.assertEqual( switch.defaultDpid(), switch.dpid )
+
+    def testActualDpidAssignment( self ):
+        """Verify that Switch dpid is the actual dpid assigned if dpid is 
+        passed in switch creation."""
+        mn = Mininet( Topo() )
+        switch = mn.addSwitch( 'A', dpid = '000000000000ABCD' )
+        self.assertEqual( switch.dpid, '000000000000ABCD' )
+
+    def testDefaultDpidAssignmentFailure( self ):
+        """Verify that Default dpid assignment raises an Exception if the 
+        name of the switch does not contin a digit. Also verify the 
+        exception message."""
+        mn = Mininet( Topo() )
+        with self.assertRaises( Exception ) as raises_cm:
+            switch = mn.addSwitch( 'A' )
+        self.assertEqual(raises_cm.exception.message, 'Unable to derive '
+                         'default datapath ID - please either specify a dpid '
+                         'or use a canonical switch name such as s23.')
+
+    def testDefaultDpidLen( self ):
+        """Verify that Default dpid length is 16 characters consisting of
+        16 - len(hex of first string of contiguous digits passed in switch
+        name) 0's followed by hex of first string of contiguous digits passed
+        in switch name."""
+        mn = Mininet( Topo() )
+        switch = mn.addSwitch( 's123' )
+        dpid = int(re.findall( r'\d+', switch.name ) [0])
+        dpid = hex( dpid ) [ 2: ]
+        self.assertEqual( switch.dpid, '0' * (16 - len(dpid)) + str(dpid) )
+
+
+if __name__ == '__main__':
+    setLogLevel( 'warning' )
+    unittest.main()