Github user Savalek commented on the issue:
https://github.com/apache/zeppelin/pull/3235
@felixcheung, these tests should fall, because `maven` incorrectly handled
errors when testing through `npm`. This PR is only the first part of fixing
problems. The second part is the correction of those tests that have been
falling for a long time, but because of the bug of the `frontend maven plugin
1.4`, `travis` shows that the `npm` tests have passed, but in fact this is not
the case.---
