Apologies, but I've been writing more code than blogs recently. My attention has been focused on Node recently and I've done some cool things: my first npm package, custom build environments for Sublime Text 3 (JSHint and Node Inspector), and a bunch of stuff I can't think of right now. Sure, I've been a crappy blogger, but I've been learning constantly. Since I would rather be a badass JS developer than a badass blogger, that's OK.

For convenience, I've been adding notes to the README.md file in the projects on Github. This is much easier than the whole blog thing. But, for you, my imaginary reader, I'm going to attempt to copy the html here.

update: Blogger doesn't want to play nicely with the Markdown styles, so I suggest reading it here.

Learn Mocha

This is a simple project to learn about Mocha.

Notes

Set Up

Start by initializing npm.
npm init
Walk through the steps to get a basic package.json.
Add mocha to the package. Add package dependencies through the console for convenience.
npm install mocha --save-dev
This adds it to package.json under "devDependencies".
Set up an npm script in package.json to test using the installed Mocha.

"scripts": {
    "test": "node_modules/.bin/mocha"
},

Add test/test.js to your project. This is where Mocha looks for tests by default.
If no file is specified when calling mocha, all *.js files in the ./test directory will be run. You can make it search recursively through the test dir with --recursive.
Now, running this from the console will execute the test cases in ./test.

npm test

This executes the "test" defined in package.json's "scripts".

Writing Tests

This has just wired up Mocha so far, which is the testing framework. The test(s) need to specify an assertion library to use. You can use Node's or anything else that throws errors (ie. write your own).

Asynchronous Tests

To make a test async, use the following format.

it('should work asynchronously', function (done) {
    // do some assertions
    done();
});

If you're testing something that returns a promise, use

it('should work asynchronously', function () {
    return stuff().should.eventually.be(true);
});

Pending Test Cases

When you're not sure how to write the assertion for a test case, you can leave it out. This will show the test as "pending" when run.

it('is a pending test case');

Only

When you just want to run one suite or test, add only.

describe.only('only this suite will run', function () {
    it('should test stuff');
    it('should test other stuff');
});

Specify a Reporter

You just get the dot-matrix reporter by default. You can specify others with --reporter foo. Add this to the package.json "test" entry. You can see the available reporters with
./node_modules/.bin/mocha --reporters

Watch Files for Changes

--watch watches for changings to the test file and any .js file in cwd. This is sweet.

Using a Makefile

According to Mocha's best practices, it's a good idea to "add a make test target to your Makefile". I'm not in the habit of providing a Makefile, but it's not that bad.

# The name of the file make will try to generate.
# If "test" already exists, make will not run the
# "recipe" for it.
test:
    # This is a "recipe", the commands used to create
    # the file "test".
    ./node_modules/.bin/mocha --reporter nyan

# Indicate that "test" is not a file to be created,
# but a task to execute.  This means it will always
# run the "recipe", even if "test" already exists.
.PHONY: test

From the terminal, you can now run make test and it will run the "recipe" specified above. For that matter, you can just run make since it's the only thing in there. (make ref)

Jeremy Greer

Friday, May 23, 2014

Hello, Mocha