Merge pull request #12810 from edx/andya/no-karma-firefox-modals

Don't auto-update during Karma test runs

common/static/common/js/karma.common.conf.js

@@ -325,8 +325,18 @@ var getBaseConfig = function (config, useRequireJs) {
 
         // start these browsers
         // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
-        browsers: ['Firefox'],
-
+        browsers: ['FirefoxNoUpdates'],
+
+        customLaunchers: {
+            // Firefox configuration that doesn't perform auto-updates
+            FirefoxNoUpdates: {
+                base: 'Firefox',
+                prefs: {
+                    'app.update.auto': false,
+                    'app.update.enabled': false
+                }
+            }
+        },
 
         // Continuous Integration mode
         // if true, Karma captures browsers, runs the tests and exits