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

examples/test/test_cpu.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+"""TEST"""
+
+import unittest
+import pexpect
+from mininet.log import setLogLevel
+
+class testCPU( unittest.TestCase ):
+    "Test ping with single switch topology (common code)."
+
+    prompt = 'mininet>'
+
+    def testCPU( self ):
+        opts = [ '([a-z]+)\t([\d\.]+)%\t([\d\.]+)', pexpect.EOF ]
+        p = pexpect.spawn( 'python -m mininet.examples.cpu' )
+        scheds = []
+        while True:
+            index = p.expect( opts, timeout=600 )
+            if index == 0:
+                sched = p.match.group( 1 ) 
+                cpu = float( p.match.group( 2 ) )
+                bw = float( p.match.group( 3 ) )
+                if sched not in scheds:
+                    scheds.append( sched )
+                    previous_bw = 10 ** 4 # 10 GB/s
+                self.assertTrue( bw < previous_bw )
+                previous_bw = bw
+            else:
+                break
+
+        self.assertTrue( len( scheds ) > 0 )
+
+if __name__ == '__main__':
+    setLogLevel( 'warning' )
+    unittest.main()