Proofwiki uses TLSv1.2 only, which is explicitly rejected by early Ubuntu precise images. Ubuntu fixed this in May 2015, but Travis is using images before that.
The workaround for Travis is to use newer ssl libraries on the Ubuntu precise image.
```
3672FAIL: test_detect_site (tests.site_detect_tests.SiteDetectionTestCase)
3673Test detection of MediaWiki sites.
3674----------------------------------------------------------------------
3675Traceback (most recent call last):
3676 File "/home/travis/build/wikimedia/pywikibot-core/tests/site_detect_tests.py", line 183, in test_detect_site
3677 self.assertAllPass()
3678 File "/home/travis/build/wikimedia/pywikibot-core/tests/site_detect_tests.py", line 115, in assertAllPass
3679 self.assertEqual(set(self.passes), set(self.all) - set(self.skips))
3680AssertionError: Items in the second set but not the first:
3681'http://www.proofwiki.org/wiki/$1'
```
https://travis-ci.org/wikimedia/pywikibot-core/jobs/128508437