gitlab CI: add support for DRM-backend tests

In order to run DRM-backend tests, a DRM-device is needed. As we
do not necessarily have control of the hardware that is going to
run our tests in GitLab CI, DRM-backend tests were being skipped.
This patch add support to run the tests using VKMS (virtual KMS).
To achieve this, virtualization is needed, as we need to run a
custom kernel during the CI job. We've decided to go with virtme,
as it is simpler to setup and works good for our use case.

Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>

.gitlab-ci/virtme-scripts/run-weston-tests.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# folders that are necessary to run Weston tests
+mkdir -p /tmp/tests
+mkdir -p /tmp/.X11-unix
+chmod -R 0700 /tmp
+
+# set environment variables to run Weston tests
+export XDG_RUNTIME_DIR=/tmp/tests
+export WESTON_TEST_SUITE_DRM_DEVICE=card0
+
+# ninja test depends on meson, and meson itself looks for its modules on folder
+# $HOME/.local/lib/pythonX.Y/site-packages (the Python version may differ).
+# virtme starts with HOME=/tmp/roothome, but as we installed meson on user root,
+# meson can not find its modules. So we change the HOME env var to fix that.
+export HOME=/root
+
+# run the tests and save the exit status
+ninja test
+TEST_RES=$?
+
+# create a file to keep the result of this script:
+#   - 0 means the script succeeded
+#   - 1 means the tests failed, so the job itself should fail
+TESTS_RES_PATH=$(pwd)/tests-res.txt
+echo $TEST_RES > $TESTS_RES_PATH
+
+# shutdown virtme
+sync
+poweroff -f