ci: start the dbus mock server in GN CI

.circleci/config.yml

@@ -208,7 +208,7 @@ gn-build-steps: &gn-build-steps
           ninja -C out/Default electron/build/node:headers
           export npm_config_nodedir="$PWD/out/Default/gen/node_headers"
           (cd electron/spec && npm install)
-          ./out/Default/electron electron/spec --ci --enable-logging
+          python electron/script/lib/dbus_mock.py ./out/Default/electron electron/spec --ci --enable-logging
     - store_test_results:
         path: src/junit
     - store_artifacts:

script/lib/dbus_mock.py

@@ -6,13 +6,11 @@ import os
 import sys
 
 
-def cleanup():
+def stop():
     DBusTestCase.stop_dbus(DBusTestCase.system_bus_pid)
     DBusTestCase.stop_dbus(DBusTestCase.session_bus_pid)
 
-
-atexit.register(cleanup)
-
+def start():
     dbusmock_log = sys.stdout if is_verbose_mode() else open(os.devnull, 'w')
 
     DBusTestCase.start_system_bus()
@@ -20,3 +18,11 @@ DBusTestCase.spawn_server_template('logind', None, dbusmock_log)
 
     DBusTestCase.start_session_bus()
     DBusTestCase.spawn_server_template('notification_daemon', None, dbusmock_log)
+
+if __name__ == '__main__':
+    import subprocess
+    start()
+    try:
+        subprocess.check_call(sys.argv[1:])
+    finally:
+        stop()

script/test.py

@@ -18,6 +18,9 @@ if sys.platform == 'linux2':
     # will be picked up by electron.
     try:
         import lib.dbus_mock
+        import atexit
+        lib.dbus_mock.start()
+        atexit.register(lib.dbus_mock.stop)
     except ImportError:
         # If not available, the powerMonitor tests will be skipped since
         # DBUS_SYSTEM_BUS_ADDRESS will not be set