How to start behavior tests for powermail?

Preperations

First of all, do a composer update in powermail root folder
You have to install a local TYPO3-instance in the next step and it should be available under powermail.localhost.de
Move (or symlink) the powermail-Folder into typo3conf/ext/ and activate the extension.
Them import the database dump from http://powermail.in2code.ws/fileadmin/behat/powermail.sql.gz

Command line

Start Selenium

Download geckodriver from https://github.com/mozilla/geckodriver/releases, make it executable and move it to /usr/local/bin/
Open a console and go to EXT:powermail/Tests/Behavior/
Start a selenium server with sh selenium.sh
As an alternative, you could specify which browser version should be used (if you installed a second firefox - probably older then quantum) - in my case: java -jar ../../.Build/vendor/se/selenium-server-standalone/bin/selenium-server-standalone.jar -Dwebdriver.firefox.bin="/var/www/Webtools/firefox/42/firefox"

Start Behat

Open another console and go to EXT:powermail/Tests/Behavior/
Start behat with sh behat.sh or with sh behats.sh (for stopping on first failure)
As an alternative, you could specify a single test by its tag like sh behatt.sh Pi1Default (to start all tests @Pi1Default)

Screenshot

Screen from the huge testparcours that has to be passed before every release: