Flaky test - org.apache.zeppelin.python.IPythonInterpreterTest.testIPythonPlotting

Tests run: 11, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 71.611 sec <<< FAILURE! - in org.apache.zeppelin.python.IPythonInterpreterTest
testIPythonPlotting(org.apache.zeppelin.python.IPythonInterpreterTest)  Time elapsed: 4.674 sec  <<< FAILURE!
java.lang.AssertionError: expected:<2> but was:<3>
	at org.junit.Assert.fail(Assert.java:88)
	at org.junit.Assert.failNotEquals(Assert.java:834)
	at org.junit.Assert.assertEquals(Assert.java:645)
	at org.junit.Assert.assertEquals(Assert.java:631)
	at org.apache.zeppelin.python.IPythonInterpreterTest.testIPythonPlotting(IPythonInterpreterTest.java:234)

Running org.apache.zeppelin.python.PythonDockerInterpreterTest
 WARN [2019-09-24 20:54:09,148] ({Exec Default Executor} ProcessLauncher.java[onProcessFailed]:111) - Process is failed due to org.apache.commons.exec.ExecuteException: Process exited with an error: 143 (Exit value: 143)
 INFO [2019-09-24 20:54:09,148] ({Exec Default Executor} ProcessLauncher.java[transition]:86) - Process state is transitioned to TERMINATED
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec - in org.apache.zeppelin.python.PythonDockerInterpreterTest

Results :

Failed tests: 
  IPythonInterpreterTest.testIPythonPlotting:234 expected:<2> but was:<3>

Tests run: 33, Failures: 1, Errors: 0, Skipped: 0