The Librarian: Introduction to Test-Driven Development

This will be a series of articles revolving around unit testing where I will work through examples and exploring various aspects of the craft. This is the first installment.

The code associated with this article can be found on GitHub. Future and past installments can be found in The Librarian Archive.

I will try to implement a few requirements for a Library module with books and memberships, extending whatever code we have in a test-driven style (“TDD”) as we go along. I share a few thoughts about the process, show some refactorings and give a few hints for using the IDE.

The level of this article is for junior developers who want to expand their testing horizon.

There’s plenty of information out there which describes what TDD or Test-Driven Development is, the red-green-refactor cycle etc so I won’t delve into too much introductory detail here. See the references at the end for more background-information.

Instead, just get started!

So If You’re Using Tag Libraries for Your View Models You Have To Test Them, Right?

In a previous post I introduced thinking about (visual) components and used a Task Browser as an example of an user interface “component” .

I explained that using

• View Model(s) e.g. plain-old Groovy objects (POGOs) holding the related data e.g. a class TaskBrowser
• Tag Libraries (LayoutTagLib) and tags (def taskBrowser) to render the associated HTML (views/layouts/components/_taskBrowser.gsp) to the page

allows for more maintainable and testable code.

Let’s put our money where our mouth is and see how one could test the used tag library.