It first appeared here, on the py2.7 build only
https://travis-ci.org/wikimedia/pywikibot-core/jobs/29067805
And then in the next build it disappeared.
It is back again:
https://travis-ci.org/wikimedia/pywikibot-core/jobs/29843942
This is almost certainly a problem with the utility method get_test_unconnected_page, which is a rough hack and should be replaced with a generator, or made more robust.
Version: core-(2.0)
Severity: normal