False is not true

Traceback (most recent call last):
  File "/home/jenkins/workspace/Spark-1.6-SBT/AMPLAB_JENKINS_BUILD_PROFILE/hadoop2.3/label/spark-test/python/pyspark/streaming/tests.py", line 1433, in test_mqtt_stream
    self._retry_or_timeout(retry)
  File "/home/jenkins/workspace/Spark-1.6-SBT/AMPLAB_JENKINS_BUILD_PROFILE/hadoop2.3/label/spark-test/python/pyspark/streaming/tests.py", line 1439, in _retry_or_timeout
    test_func()
  File "/home/jenkins/workspace/Spark-1.6-SBT/AMPLAB_JENKINS_BUILD_PROFILE/hadoop2.3/label/spark-test/python/pyspark/streaming/tests.py", line 1429, in retry
    self.assertTrue(len(result) > 0)
AssertionError: False is not true