Hi
what is "MoodleSessionTest" cookie for and from what is it different from the "MoodleSession" cookie ?
anyone?
Well, was something used in the past for testing the Moodle session
a test session will still oddly pop up if a user has disabled cookies in their browser and therefore can't log in to moodle.
No it won't. There is no mention of that cookie name anywhere in the code since 2.0.
I did that search as well and did not find direct traces of it. But I do remember I used to see that cookie set by Moodle sites, too. IIRC, it (or something similar to it) was used to test that the cookies mechanism actually works, by setting and re-reading the value, or something like that (Petr Škoda might remember details). May it be that you have the $CFG->sessioncookie set to 'Test' for some reason? In that case, the following code $sessionname = 'MoodleSession'.$CFG->sessioncookie; could still lead to setting it, but I admit it's not very probable.

it's an optional param on the login which is used to verify that sessions are working.
https://github.com/moodle/moodle/blob/master/login/index.php#L38
https://github.com/moodle/moodle/blob/master/login/index.php#L57-L72