Question

I don’t see how to do test driven development in meteor.

I don’t see it mentioned anywhere in documentation or FAQ. I don’t see any examples or anything like that.

I see that some packages are using Tinytest.

I would need response from developers, what is roadmap regarding this. Something along the lines of:

• possible, no documentation, figure it out yourself
• meteor is not built in a way that you can make testable apps
• this is planned feature
• etc

Answer 1

Update 3: As of Meteor 1.3, meteor includes a testing guide with step-by-step instructions for unit, integration, acceptance, and load testing.

Update 2: As of November 9th, 2015, Velocity is no longer maintained. Xolv.io is focusing their efforts on Chimp, and the Meteor Development Group must choose an official testing framework.

Update: Velocity is Meteor’s official testing solution as of 0.8.1.

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Not much has been written about automated testing with Meteor at this time. I expect the Meteor community to evolve testing best-practices before establishing anything in the official documentation. After all, Meteor reached 0.5 this week, and things are still changing rapidly.

The good news: you can use Node.js testing tools with Meteor.

For my Meteor project, I run my unit tests with Mocha using Chai for assertions. If you don’t need Chai’s full feature set, I recommend using should.js instead. I only have unit tests at the moment, though you can write integration tests with Mocha as well.

Be sure to place your tests in the “tests” folder so that Meteor does not attempt to execute your tests.

Mocha supports CoffeeScript, my choice of scripting language for Meteor projects. Here’s a sample Cakefile with tasks for running your Mocha tests. If you are using JS with Meteor, feel free to adapt the commands for a Makefile.

Your Meteor models will need a slight bit of modification to expose themselves to Mocha, and this requires some knowledge of how Node.js works. Think of each Node.js file as being executed within its own scope. Meteor automatically exposes objects in different files to one another, but ordinary Node applications—like Mocha—do not do this. To make our models testable by Mocha, export each Meteor model with the following CoffeeScript pattern:

# Export our class to Node.js when running
# other modules, e.g. our Mocha tests
#
# Place this at the bottom of our Model.coffee
# file after our Model class has been defined.
exports.Model = Model unless Meteor?

…and at the top of your Mocha test, import the model you wish to test:

# Need to use Coffeescript's destructuring to reference
# the object bound in the returned scope
# http://coffeescript.org/#destructuring
{Model} = require '../path/to/model'

With that, you can start writing and running unit tests with your Meteor project!