I have a project on github that has extensive unit tests (using mocha for node.js).
I'd like to show off by showing those tests passing/failing on each page. I notice other projects on Github are doing this.
I've been unable to find any documentation on how to make the test status display.
Take a look at Travis CI. You can use it with GitHub.
They have docs on using NodeJS
Those badges you see are called "status images" and Travis provides MarkDown that you can insert into your project's README.md file.