This test seems to fail randomly, see for instance [[https://integration.wikimedia.org/ci/job/wmf-quibble-vendor-mysql-hhvm-docker/8061/console|this log]].Several Flow tests fail randomly, It happened another couple of times for different patches,see traces below; and aa recheck has always solveds the problem.
```
08:42:12 1) Flow\Tests\Collection\PostCollectionTest::testGetFirstRevision
08:42:12 Failed asserting that false is true.
08:42:12
08:42:12 /workspace/src/extensions/Flow/tests/phpunit/Collection/PostCollectionTest.php:10090
08:42:12 /workspace/src/tests/phpunit/MediaWikiTestCase.php:424
08:42:12 /workspace/src/maintenance/doMaintenance.php:94
```
```
23:02:04 1) Flow\Tests\Api\ApiFlowModerateTopicTest::testModerateLockedTopic
23:02:04 Wikimedia\Rdbms\DBQueryError: A database query error has occurred. Did you forget to run your application's database schema updater after upgrading?
23:02:04 Query: INSERT INTO `unittest_flow_revision` (rev_id,rev_user_id,rev_user_ip,rev_user_wiki,rev_parent_id,rev_change_type,rev_type,rev_type_id,rev_content,rev_flags,rev_mod_state,rev_mod_user_id,rev_mod_user_ip,rev_mod_user_wiki,rev_mod_timestamp,rev_mod_reason,rev_last_edit_id,rev_edit_user_id,rev_edit_user_ip,rev_edit_user_wiki,rev_content_length,rev_previous_content_length) VALUES ('�z#p�4:��','1',NULL,'wikidb-unittest_','�z#p��4:��','delete-topic','post','�z#p��4:��','Hi there!','utf-8,topic-title-wikitext','delete','1',NULL,'wikidb-unittest_','20181116215905','<>&{};',NULL,NULL,NULL,NULL,'0','9')
23:02:04 Function: Flow\Data\Storage\RevisionStorage::insert
23:02:04 Error: 1062 Duplicate entry '\x05\x9Cz#p\xA3\xFE4:\x9C\xED' for key 'flow_revision_unique_parent' (/workspace/db/quibble-mysql-a08yeqot/socket)
```