Arie van Deursen

Teaching Testing in Year One

Starting 2013/2014, TU Delft will run a revised curriculum for the bachelor computer science. The software testing course that I have been teaching to 2nd and 3rd year CS students will move from to the (end of) the first year.

This is an exciting prospect. It confirms that testing is not an afterthought, but something that should be built into software development right from the start.

But can it be done? What should freshmen coming straight from high school be taught before they can start with testing? And what should a first year testing course contain?

To build up the required knowledge, the TU Delft curriculum anticipates three pre-testing courses.

  1. In the first, students learn about object-oriented programming, covering topics ranging from simple loops to inheritance, polymorphism, and interfaces. They will even learn a bit about the mechanics of testing their code automatically.
  2. Subsequently, they use the acquired programming skills in a simple project. They learn to work in teams, to write software according to requirements provided by others, and to share their (UML) design diagrams with other team members.
  3. As the third step, they learn about data structures such as linked lists or binary search trees, and learn to use recursion. These courses (object-oriented programming, a project, and data structures), are scheduled for the first three quarters of the first year.

Then in the fourth quarter, a dedicated course on software testing comes in. The course should hook students to innovative forms of testing for the rest of their lives. Here’s what I have in mind for that.

The practical basis will include exploratory testing, behavior-driven development, and the use of testable scenarios to specify requirements. With respect to unit testing, the students will learn JUnit, the use of build tools (maven), coverage analysis, and the use of continuous integration tools (Jenkins). I even hope to get them to understand a mocking framework like Mockito. Students will apply these techniques to a small existing applications (JPacman) which they will have to adapt and test.

The more theoretical basis will be provided by the systematic derivation of test cases from models, such as state machines or decision tables. Furthermore, I’ll elaborate on different adequacy models (beyond statement coverage!) as well as combinatorial testing techniques (e.g., pairwise testing).

This being an academic course, it will also include a critical reflection on the tools and techniques covered. We’ll identify strengths and weaknesses, and see how today’s hottest research aims at addressing these weaknesses.

Well, perhaps this is all too ambitious. I will try, and we will see. Luckily, TU Delft is not the first university to move testing to the first year: Eindhoven is a notable other example, and I am sure there are more (although perhaps not many). “Test early, test often” — learn it early, apply it often.