Coverage report with istanbul and mocha - node.js

Question

I'm a newbie on Node.js. I have to set up some tests in my application and I'm getting really mad trying to generate a back-end code coverage report with mocha and istanbul in my loopback application.
Searching through thousand of dab explained articles on Github I found some good articles and then I figured out that I had to use something like this:
istanbul cover _mocha -- [path/to/test/files] -R spec
I was happy because it says: "What you are essentially doing is passing the command to run your tests to Istanbul which, in turn, will run those tests on your behalf." However, every time I try to run Istanbul, I get this error:
No coverage information was collected, exit without writing coverage information
C:\...\proj-name\node_modules\.bin\_mocha:2
basedir=$(dirname "$(echo "$0" | sed -e 's,\\,/,g')")
^^^^^^^
SyntaxError: missing ) after argument list
My working test file is:
var userService = require('../TestBusinessLogic.js');
var should = require('chai').should();
describe('API Utenti', function() {
it('should throw Exception on missing UserName', function() {
(function() {
userService({ Name: 'Pippo', Surname: 'Baudo' });
}).should.Throw(Error);
});
});
Is this command good to use? If not, could someone please explain me how to make a coverage report using istanbul with mocha?

Answer 1

Figured that I was running node_modules\.bin\_mocha instead of node_modules\mocha\bin\_mocha and this solved my problem.

Answer 2

When running istanbul from the command line you need to run it from the root of your project directory, it by default looks for the files to run the coverage reporting for at the root of your directory.
Additionally make sure your path to your test folder is relative to your project directory.
So you should navigate to your project directory using cd and then when inside your project directory then run
istanbul cover _mocha -- ./path-to/test.js -R spec