Add example unit tests and Makefile target

Makefile

 clean:
-	rm -rf build dist build *.egg-info *.pyc
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+	rm -rf build dist build *.egg-info *.pyc
+
+test: mininet/*.py mininet/test/*.py
+	mininet/test/test_nets.py
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mininet/mininet.py

@@ -73,6 +73,8 @@
 flush = sys.stdout.flush
 from resource import setrlimit, RLIMIT_NPROC, RLIMIT_NOFILE
 
+DATAPATHS = ['user', 'kernel']
+
 # Utility routines to make it easier to run commands
 
 def run( cmd ):

mininet/test/test_nets.py

+#!/usr/bin/env python
+'''@package mininet
+
+Test creation and all-pairs ping for each included mininet topo type.
+'''
+
+from time import sleep
+import unittest
+
+from mininet.mininet import init, TreeNet, pingTest, DATAPATHS
+
+class testMinimal(unittest.TestCase):
+    '''For each datapath type, test ping with a minimal topology.
+
+    Each topology has two hosts and one switch.
+    '''
+
+    def testMinimal(self):
+        '''Ping test with user-space datapath on minimal topology'''
+        init()
+        for datapath in DATAPATHS:
+            k = datapath == 'kernel'
+            network = TreeNet(depth = 1, fanout = 2, kernel = k)
+            dropped = network.run(pingTest)
+            self.assertEqual(dropped, 0)
+
+
+class testTree(unittest.TestCase):
+    '''For each datapath type, test all-pairs ping with TreeNet.'''
+
+    def testTree16(self):
+        '''Ping test with user-space datapath on minimal topology'''
+        init()
+        for datapath in DATAPATHS:
+            k = datapath == 'kernel'
+            network = TreeNet(depth = 2, fanout = 4, kernel = k)
+            dropped = network.run(pingTest)
+            self.assertEqual(dropped, 0)
+
+
+if __name__ == '__main__':
+    unittest.main()
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