ZEPPELIN-1063: fix flaky python interpreter test

[bzz]

What is this PR for?

fix flaky python interpreter test

What type of PR is it?

Bug Fix

Todos

• cleanup test code
• fix flaky open port check

What is the Jira issue?

ZEPPELIN-1063

How should this be tested?

mvn "-Dtest=org.apache.zeppelin.python.PythonInterpreterTest" test -pl python

Questions:

• Does the licenses files need update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[bzz]

Ready to be merged, \cc @minahlee@prabhjyotsingh for review.

Current CI failure is being taken care of under #1092

[bzz]

Rebased on latest master, after #1092 got merged

[bzz]

CI fails on Integration tests, and failure looks different from #1091 and #1092

Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 143.455 sec - in org.apache.zeppelin.integration.ZeppelinIT
Results :
Tests in error: ParagraphActionsIT.testClearOutputButton:285->AbstractZeppelinIT.waitForParagraph:70->AbstractZeppelinIT.pollingWait:96 » Timeout
Tests run: 15, Failures: 0, Errors: 1, Skipped: 0

@prabhjyotsingh any chance you you seen this before?

[bzz]

CI failure is not related and logged under ZEPPELIN-1073
Merging if there is no further disucssion

[prabhjyotsingh]

Yes, I've seen this, this happens when spark takes longer that 60sec to start up.
Will open up a new jira and fix this as well.