ci: Start dbus session bus for testing

A dbus session bus must be started for testing. The command
`dbus-run-session` creates a session for the following command. As a
result, `pytest` runs with its own session bus for the tests.

Signed-off-by: Sven Sager <s.sager@kunbus.com>

.gitlab-ci.yml

@@ -30,7 +30,7 @@ run_tests:
     - apt-get -y install dbus libgirepository1.0-dev
     - dbus-uuidgen --ensure=/etc/machine-id
     - pip install -r requirements.txt
-    - PYTHONPATH=src pytest -v --junitxml=report.xml --cov=src --cov-report term --cov-report xml:coverage.xml
+    - PYTHONPATH=src dbus-run-session -- pytest -v --junitxml=report.xml --cov=src --cov-report term --cov-report xml:coverage.xml
   coverage: '/(?i)total.*? (100(?:\.0+)?\%|[1-9]?\d(?:\.\d+)?\%)$/'
   artifacts:
     reports: