[FIX] tests: properly stop chrome when no tab found

In some situations, Chrome remote debugging is sending an empty list of
opened tabs. In that case, an orphan Chrome process stays alive.

With this commit, Chrome is stopped properly in those situations.

odoo/tests/common.py

@@ -351,6 +351,7 @@ class ChromeBrowser():
         self.chrome_process = None
         self.screencast_frames = []
         self._chrome_start()
+        self._find_websocket()
         self._logger.info('Websocket url found: %s', self.ws_url)
         self._open_websocket()
         self._logger.info('Enable chrome headless console log notification')
@@ -419,9 +420,16 @@ class ChromeBrowser():
         except OSError:
             raise unittest.SkipTest("%s not found" % cmd[0])
         self._logger.info('Chrome pid: %s', self.chrome_process.pid)
+
+    def _find_websocket(self):
         version = self._json_command('version')
         self._logger.info('Browser version: %s', version['Browser'])
-        infos = self._json_command('')[0]  # Infos about the first tab
+        try:
+            infos = self._json_command('')[0]  # Infos about the first tab
+        except IndexError:
+            self._logger.warning('No tab found in Chrome')
+            self.stop()
+            raise unittest.SkipTest('No tab found in Chrome')
         self.ws_url = infos['webSocketDebuggerUrl']
         self._logger.info('Chrome headless temporary user profile dir: %s', self.user_data_dir)