We had a test scenario which behaves differently on CI than local environment and we can't find any reason.
Please see this PR: https://github.com/martamedio/liferay-portal/pull/157
In this test we're trying to launch a request using Portal Session Authentication to check CORS functionality, so we're trying to recover a Portal Session Cookie (_getAuthenticatedCookie()):
1. Request to "web/request" to obtain an _p_auth_ token
2. Second request to log in as firstname.lastname@example.org/test
3. After the previous request we detected locally that we need to perform redirection (this request fails on CI)
4. We try to obtain a cookie to launch our test, but after the failed redirection we obtain an Exception trying to find that cookie.
If you run this test in a local environment, it works perfectly.
Also note that we have a similar test in OAuth2 module, where there has been no problem getting this cookie.