single run have to be specify in the package.json command otherwise the browser test can not be executed

ng2-components/ng2-alfresco-core/karma.conf.js

@@ -75,8 +75,7 @@ module.exports = function (config) {
                 {type: 'json', file: 'coverage-final.json'},
                 {type: 'html'}
             ]
-        },
+        }
 
-        singleRun: true
     })
 };