CodeCov.io Demonstration

CodeCov.io is a service that automatically presents code coverage reports generated by continuous integration builds. This tutorial will take you through setting up a Travis CI build and subsequently generating a code coverage report for it.

First Steps

Create a new repository on GitHub with a Node .gitignore. Clone this repo and initialise a node project with

npm init

(Add the --y flag to skip filling in the package.json file and inputs blanks)

Then install codecov and istanbul as developer dependencies with the command

npm install codecov --save-dev
npm install istanbul --save-dev

Then in the scripts field of package.json, add

"test": "node ./node_modules/.bin/istanbul cover test.js && ./node_modules/.bin/codecov"

Let's break down what's happening in this command. Firstly, with node ./node_modules/.bin/istanbul cover test.js we are running the istanbul code coverage generator on the test.js file. See this tutorial for more on how Istanbul works.

If that executes successfully, the codecov script is executed. It will scan for code coverage reports and then send them off to the CodeCov API.

Just for reference, you can see our (rather trivial) test.js file below.

var x = 1, z;

var y = 3*x;

if (y > 20) {
    z = 5;
} else {
    z = 7;
}

Building with Travis CI

Travis CI is a FOSS, hosted, distributed continuous integration service used to build and test software projects hosted at GitHub

Steps to setting up travis

Sign up to Travis here

Once signed up allow travis build access to your github repository through accounts and then selecting your organisation

Allow a build request only if a .travis.yml is present

To create a .travis.yml file, in your directory simply run

touch .travis.yml

and add your language and your current version to the file

language: node_js
node_js:
  - "4.1"

Then all subsequent git push commands will trigger a new build, which by default runs the npm test command.

Documentation

You can read their documentation and their 'Getting Started' guide here.

Checking your Coverage on CodeCov.io

If your Travis build has run successfully, you should see the following console output in the build status window:

Note in particular the final line, giving you the URL to view your code coverage report online.

Either visit this URL, or sign in to CodeCov using your github account and navigate to the repo in question. You should see this dashboard:

Navigate inside to see more detailed statistics

And thats it!

Bonus Challenge

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