[gjs] build: Run coverage jobs in XVFB

[Philip Chimento <pchimento src gnome org>]

commit 272cee79f40d0f8f46dc660554325c388e3ee640
Author: Philip Chimento <philip chimento gmail com>
Date:   Mon Oct 28 11:38:56 2019 -0700

    build: Run coverage jobs in XVFB
    
    Otherwise we don't get code coverage from any tests that require an X11
    display.
    
    Unreviewed, pushing to fix coverage build.

 .gitlab-ci.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 953c6778..6efc8325 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -18,9 +18,10 @@ stages:
   script:
     - export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
     - export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
+    - 'export DISPLAY="${DISPLAY:-:0}"'
     # This script runs the build inside its own build tree and generates the
     # coverage report
-    - tools/run_coverage.sh
+    - xvfb-run -a tools/run_coverage.sh
   artifacts:
     name: log_coverage
     when: always