adding first draft of tests for all examples, they need comments and clean up, some could be made more rebust

examples/test/test_nat.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+
+"""TEST"""
+
+import unittest
+import pexpect
+#from time import sleep
+from mininet.log import setLogLevel
+#from mininet.net import Mininet
+#from mininet.node import CPULimitedHost
+#from mininet.link import TCLink
+
+#from mininet.examples.simpleperf import SingleSwitchTopo
+
+class testNAT( unittest.TestCase ):
+    "Test ping with single switch topology (common code)."
+
+    prompt = 'mininet>'
+
+    # skip if 8.8.8.8 unreachable
+    def testNAT( self ):
+        p = pexpect.spawn( 'python -m mininet.examples.nat' )
+        p.expect( self.prompt )
+        p.sendline( 'h1 ping -c 1 8.8.8.8' )
+        p.expect ( '(\d+)% packet loss' )
+        percent = int( p.match.group( 1 ) ) if p.match else -1
+        p.expect( self.prompt )
+        p.sendline( 'exit' )
+        p.wait()
+        self.assertEqual( percent, 0 )
+    '''
+    def testTopo( self ):
+        topo = SingleSwitchTopo(n=4)
+        net = Mininet(topo=topo,
+                  host=CPULimitedHost, link=TCLink)
+        net.start()
+        h1, h4 = net.get('h1', 'h4')
+        h1.cmd( 'ping -c 1 %s' % h4.IP() )
+        net.stop()
+    '''
+
+if __name__ == '__main__':
+    setLogLevel( 'warning' )
+    unittest.main()