'Start Mininet using a custom topo, then run pingall'

def testCustomTopo(self):

    assert self
    custom = os.path.dirname(os.path.realpath(__file__))
    custom = os.path.join(custom, '../../custom/topo-2sw-2host.py')
    custom = os.path.normpath(custom)
    p = pexpect.spawn(('mn    --custom    %s    --topo    mytopo    --test    pingall' % custom))
    p.expect('0%    dropped')
    p.expect(pexpect.EOF)
