Table of Contents for

JavaScript Testing with Jasmine

First, you need to install the jasmine-node package. Type the following into your terminal:

  sudo npm install -g jasmine-node

The -g flag installs jasmine-node on your system globally. If you’d prefer to keep it in a project directory, leave the flag off. This also (probably) means you don’t need sudo at the front.

First, download a ZIP of jasmine-node.

Unpack it and rename the folder as jasmine-node. Once you do this, move it into the same directory that you installed node.exe into. You should be up and running!

Now you have jasmine-node installed! Use it as follows:

  jasmine-node /path/to/project/directory

Jasmine-node requires you to put your specs in a directory called spec and for the specs in that directory to end with .spec.js. You can also put specs in subdirectories of the spec directory.

For example, if you have a function like this in src/test.js:

  global.hello = function() {
      return 'world';
  };

A test spec for that might look like this:

  // Include what we need to include: this is specific to jasmine-node
  require("../src/test.js");

  describe("hello", function() {
      it('returns "world"', function() {
          expect(hello()).toEqual("world");
      });
  });

Other than the require calls that you need to make, the specs are just like browser-based Jasmine specs—except for one asynchronous component, that is.

Asynchronous tests work the same way as they do in “regular” Jasmine, but there’s another syntax that you can use: the done function. This signals to jasmine-node that your spec is, well, done.

Here’s an example of how you’d use it:

  it("does an asynchronous call", function() {
      exampleAsyncCall(function(response) {
          expect(response).toContain("something expected");
          done();
      });
  });

The done function says to jasmine-node: “Hey, this is a function that deals with asynchronous stuff. Don’t call it quits until done is called…unless it takes too long and things time out (after 5 seconds).” You can adjust this timeout value by changing jasmine.DEFAULT_TIMEOUT_INTERVAL, like so:

  // Change default timeout interval to 2 seconds
  jasmine.DEFAULT_TIMEOUT_INTERVAL = 2000;

If you want to use jasmine-node with CoffeeScript, you can. You’ll need to end your filenames with .spec.coffee and then run jasmine-node with the --coffee flag, like so:

  jasmine-node /path/to/project/directory --coffee

That’s all you have to do! Jasmine-node will start picking up .spec.coffee files and test them properly.

First, you’ll need to add Jasmine to your Gemfile, like so:

  gem "jasmine"

Next, let’s install it:

  bundle install
  rails generate jasmine:install

Now you’re all set up! This process will create a directory called spec if you don’t already have one. Inside of that, there’s a folder called javascripts. For this example, let’s make a test spec in spec/javascripts that just contains this:

  describe("Jasmine + Rails test", function() {
      it("works", function() {
          expect(true).toBeTruthy();
      });
  });

Save this as test.spec.js.

Now, from any directory, run the following command:

  rake jasmine

After chugging a little bit, Jasmine will tell you that your tests are located at http://localhost:8888/. Visit that in your browser, and you’ll see the test pass! Now you can change test.spec.js to spec out whatever you’d like and go from there.

If you’d like to run your tests in the terminal, you can do that by running rake jasmine:ci.

If you have helpers (Jasmine plug-ins, for example), just put them in spec/javascripts/helpers and they’ll be automatically included.