| Index: test/browsers/firefox.js | 
| =================================================================== | 
| --- a/test/browsers/firefox.js | 
| +++ b/test/browsers/firefox.js | 
| @@ -33,7 +33,10 @@ | 
| exports.getDriver = function(browserBinary, devenvPath) | 
| { | 
| - let options = new firefox.Options().setBinary(browserBinary).headless(); | 
| + let options = new firefox.Options().headless(); | 
| + if (browserBinary != null) | 
| + options.setBinary(browserBinary); | 
| + | 
| let driver = new webdriver.Builder() | 
| .forBrowser("firefox") | 
| .setFirefoxOptions(options) |