Remove "Remaining deprecation notices" in Symfony 2.8

Finally found the solution !

Just add

<php>
    <env name="SYMFONY_DEPRECATIONS_HELPER" value="weak" />
</php>

to your phpunit.xml (or any other file that you use to configure phpunit)

This is a known issue of the AsseticBundle which isn't part of the official Symfony distribution anymore and not ready for 3.0 yet (having some deprecations in the current tagged version - which you can see in your error message).

So please follow and wait for this issue to be solved and update your AsseticBundle when it's ready (or go with the current master of it what I wouldn't recommend to do.

A lot of people trying to upgrade to Symfony 2.8/3.0 have this issue currently.

Link to the Issue on Github

You can run in terminal

export SYMFONY_DEPRECATIONS_HELPER=weak

Before executing your script. It will disable deprecation notices