Is there a .mocha file where I can specify defaults such as --no-colors?

Question

I'd like to set some defaults for mocha without having to type them each time. Does mocha look for a config file / dotfile anywhere, as jshint looks for .jshintrc and npm looks for package.json?

Solution 1

Yes. You can create a file ./test/mocha.opts and in the file you can specify --no-colors.

See mocha.opts on Mocha Doc for more information.

Solution 2

Mocha recommends mocha --config=.mocharc.json.

There are new formats too, like yaml. See some examples.

---

Old answer:

The default is ./test/mocha.opts. You can pass a custom path with the --opts parameter :

mocha --opts ./mocha.opts

Useful in case you don’t store your tests in test/ folder, but next to code files, for example.

Any name and extension seems to work, so you can even do mocha --opts .mocharc if you want it to go well with .jshintrc, .babelrc and the like.

Solution 3

In mocha 6+ the mocha.opts was changed to legacy and the new place to define your configuration is a .mocharc file that can have different formats (JSON, YAML, JS) as described in the docs or a JSON config added to the package.json using mocha key.

Specifying your own path to mocha config is done using --config <file> but mocha uses any .mocharc.* file as default in order described in the docs (JS, YAML, YML, JSON) and also automatically uses mocha key from package.json with lower priority than a given config file.

Comments

[ichigolas]

The accepted answer is now deprecated. I suggest accepting the new one (stackoverflow.com/a/54804446/1740079) to prevent more people from using the old approach.

[DBrown]

This is (or at least was), a very obscure function. I had given up hope for such a thing long ago, and thank you for pointing out it's possible now. :)

[Byron Whitlock]

THANK YOU! Tests should really be next to files. Locality is important!

[Jared Dykstra]

Is it possible for the contents of the file to be JSON?

[gabssnake]

It doesn’t seem like so. The CLI splits the content by spaces and then parses it with commander module. commander’s parser expects a string array. mocha source: github.com/nishigori/mocha/blob/… - commander source: github.com/tj/commander.js/blob/…

[gabssnake]

You could launch mocha in a script and pass your JSON file contents. See: github.com/mochajs/mocha/wiki/…

[andy mccullough]

strange, I couldnt get --config ./mocha.opts to work as per their official docs but --opts ./mocha.opts worked... thanks!

[Peter W]

An example .mocharc.js file is here: github.com/mochajs/mocha/blob/master/example/config/.mocharc‌​.js (and there are other formats in that directory as well).

[Katie Kilian]

This has been deprecated. See @migg's answer here.

[Martin Capodici]

This will no longer work. See: stackoverflow.com/questions/60283197/…

[gabssnake]

Thanks @MartinCapodici, updated the answer to reflect the newest mocha behavior