Node Mocha test log save to disk

Question

Need to save the test logging to the disk

I have tried the below code

  mocha -R spec  test/**/*_test.js   >  report

suppose any test case failed it not log into the 'report' file. Please suggest best way to log the test report.

Answer 1

You should redirect stderr to that logfile too:

mocha -R spec  test/**/*_test.js > report 2>&1

EDIT: if you want the contents to be sent both to a file and the console:

mocha -R spec  test/**/*_test.js 2>&1 | tee report

Answer 2

The question does not specify what the log is going to be used for. If you need stack traces in the report, then you can't use json-stream because this reporter does not include the traces. However, if what you want is something that can be parsed trivially and only thing you care about is knowing the status of the tests and not why they failed, then the json-stream reporter works nicely:

$ mocha -R json-stream > report

You get a list of regularly formatted lines:

["start",{"total":1}]
["fail",{"title":"q","fullTitle":"blah q"}]
["end",{"suites":1,"tests":1,"passes":0,"pending":0,"failures":1,"start":"2014-01-08T18:10:27.764Z","end":"2014-01-08T18:10:27.768Z","duration":4}]

Then you can grep for failed tests easily:

$ grep '^\["fail"' report

The output could also be passed to a tool that narrows it down to what you want and formats it nicely to go in an email, an IM message or something else. I've used this method quite a lot when running a test suite with thousands of tests where what I cared about most was quickly getting a list of what had failed.