问题
I am Trying to write a test using nightwatch js to validate the file is downloaded after click on button/link in the web page. No need to check data inside file, i would only require to check if the file is downloaded or not. Also before I download I have to delete the existing files from download folder so that copy of same file doesn't occur. How this can be achieved in Nightwatch js? Please help me.
来源：https://stackoverflow.com/questions/47186671/validating-download-file-in-nightwatch