Receving ERROR: TypeError: Cannot read property 'close' of undefined

I have read all the other question that I posted here but can not solve this problem
npm test -t db-connection
when i run this command it shows this error.
Moreover, I have already change the extention of config files but still getting this error.

i want to answer this question as I have solved it.
the problem is I rename the file manually like I rename the file and add the extention of .env but it. does not works so I have to run the following commands instead of manual rename.

mv dotenv_unix .env # on Unix
ren dotenv_win .env # on Windows