Currently, the SecurityBundle tests fail on Travis for versions < master when running the tests in isolation:

sh -c 'if [ "$components" = "yes" ]; then sh -c "find src/Symfony -mindepth 3 -type f -name '\''phpunit.xml.dist'\'' | sed '\''s#\(.*\)/.*#\1#'\'' | parallel --gnu --keep-order '\''echo \"Running {} tests\"; cd {}; COMPOSER_ROOT_VERSION=dev-master composer --prefer-source --dev install; phpunit --exclude-group tty,benchmark;'\''"; fi;'

The problem is that #10694 broke BC for the master branch. When the tests are run for a lower version than master ("2.3" for example), Composer still installs the dependencies in version "dev-master", resulting in errors due to the BC break.

When running the component tests, we should fix Composer to install the dependencies for the appropriate branch instead of always taking the master branch. Not sure how to do this though.

ping @romainneutron @Seldaek