Fix tests on travis

[andrerom]

Found so far:

• xenial is now default on travis, this does not seems to work with Varnish 3, stick to trusty for now
  • Bump back to xenial once we can remove Varnish3
• New version of guzzlehttp/psr7/src/MessageTrait is a bit more strict, and detects invalid parameters used in UserContextTestCase.php

[andrerom]

Unsure why this one fails:

2) FOS\HttpCache\Tests\Unit\SymfonyCache\EventDispatchingHttpCacheTest::testAddListener
Undefined index: trace_level
/home/travis/build/FriendsOfSymfony/FOSHttpCache/vendor/symfony/http-kernel/HttpCache/HttpCache.php:130
/home/travis/build/FriendsOfSymfony/FOSHttpCache/vendor/symfony/http-kernel/HttpCache/HttpCache.php:228
/home/travis/build/FriendsOfSymfony/FOSHttpCache/src/SymfonyCache/EventDispatchingHttpCache.php:98
/home/travis/build/FriendsOfSymfony/FOSHttpCache/src/Test/EventDispatchingHttpCacheTestCase.php:318

trace_level seems to be set, or?

        $this->options = array_merge([
            'debug' => false,
            'default_ttl' => 0,
            'private_headers' => ['Authorization', 'Cookie'],
            'allow_reload' => false,
            'allow_revalidate' => false,
            'stale_while_revalidate' => 2,
            'stale_if_error' => 60,
            'trace_level' => 'none',
            'trace_header' => 'X-Symfony-Cache',
        ], $options);

        if (!isset($options['trace_level']) && $this->options['debug']) {
            $this->options['trace_level'] = 'full';
        }

[dbu]

unless debug is false. i think when it is false the addTraces can still be called and will then fail in this way. it only happens with newer php versions, maybe its a recent regression that does not pop up because people are either in debug mode or ignore the undefined index in production?

[dbu]

its been added here: symfony/symfony@9a2fcc9#diff-3b14ed7783f3f7d7daf4536a9f3f1230

[dbu]

symfony/symfony#32801

[dbu]

i will merge anyways, its much better than the current state 👍

thanks @andrerom !

[dbu]

i went ahead and did a pull request to have it fixed in symfony symfony/symfony#32802