'Tasks which errored but didn\'t abort should contain an eg NetworkError'

def test_should_use_sentinel_for_tasks_that_errored(self):

    def task():
        run('whoops')
    host_string = 'localhost:1234'
    with settings(hide('everything'), skip_bad_hosts=True):
        retval = execute(task, hosts=[host_string])
    assert isinstance(retval[host_string], NetworkError)
