Begin test/example for popen().

examples/popen.py

+#!/usr/bin/python
+
+"""
+This example tests the Host.popen()/pexec() interface
+"""
+
+from mininet.net import Mininet
+from mininet.node import CPULimitedHost
+from mininet.topo import SingleSwitchTopo
+from mininet.log import setLogLevel
+# from mininet.cli import CLI
+from mininet.util import custom
+
+def testpopen(sched='cfs'):
+    "Test popen() interface"
+    host = custom( CPULimitedHost, cpu=.2, sched=sched )
+    net = Mininet( SingleSwitchTopo( 2 ), host=host )
+    net.start()
+    h1 = net.get( 'h1' )
+    # CLI(net)
+    out, err, code = h1.pexec( 'ifconfig' )
+    print 'stdout:', out.strip()
+    print 'stderr:', err.strip()
+    print 'exit code:', code
+    net.stop()
+
+if __name__ == '__main__':
+    setLogLevel( 'info' )
+    testpopen('rt')
+    testpopen('cfs')