Unit Testing for Arduino, part 2

20. January 2015 · Write a comment · Categories: Gadgets · Tags: , , , , ,

I had originally intended to spend this post discussing Ceedling, and Unity testing, but now I won’t. Why? Over the weekend, I was reading the API guide for Arduino libraries, and realized they’re heavily focused on object-oriented programming. Synthduino was written in a functional style (it’s C) – while I’d used a basic struct to hold together a note’s frequency and duration, all the calls where global functions that accepted either a note or one of its members as a parameter. This was contrary to the API.

 

I did research, trying to find a good unit testing suite for C++. Turns out I’d somehow missed what should have been a top result: Google Test (aka gTest). I had gotten distracted by the Wikipedia list of suites, and gone through there. If only…
Anyway, I’ve spent the last 2-3 days rewriting Synthduino in C++, with classes, and rewriting the test suites. Fortunately, the logic and test data is the same, so I’ve got that going for me. Once I’ve spent more time with Google Test, I’ll try to do a better comparison between it and Ceedling/Unity.

Unit Testing for Arduino, part 1

15. January 2015 · Write a comment · Categories: Gadgets · Tags: , , , , ,

Wherein our hero fights the dragons of cross-platform compatibility, libraries not being updated, inadequate documentation, and the fact that Arduino can’t do unit testing natively.

 

Why?

I’m currently working on the new release of my project Synthduino, and I’ve fallen in love with Unit Testing from various Ruby and Ruby on Rails projects I worked on last year. I decided it would be good to bring unit testing to Synthduino, not only to give me a clearer roadmap of development (unit tests help focus effort), but also make sure my work is good quality (as I do want Synthduino to be used).

What?

I briefly considered writing my own framework, but I’m not really comfortable enough in C/C++ to do it, so I looked into frameworks. Based on what I read, I narrowed it down to two options: CppUnit and Ceedling. From what I gathered, CppUnit was the more established of the two, but Ceedling was built on Ruby to use rake. I decided to try them both out.

Where?

My development platform spans 5 computers and 4 operating systems (Ubuntu, Lubuntu, Linux Mint, and Windows 7), with a git server running here. I needed something that would work moderately well on that.

How?

I started out with CppUnit. The biggest issue I ran into was the complete lack of documentation (seriously – is there any? It’s advertised as a “C++ port of JUnit” – am I supposed to use the JUnit documentation?). I looked around online and found a lot of tutorials that all used completely different ways of doing the same things. On top of that, none of them actually worked on any of my machines – every attempt to do anything, no matter how minor, was a long string of compiler errors or stack overflows.

I looked to Ceedling. Off that bat, I did like it more – it came with example projects, and included documentation (though it was hard to find). I liked the ability to use rake, which I’m familiar with, including the ability to set up stubs for everything with an easy rake command. My biggest complaint would still be that the documentation is a little sparse (and online it’s nonexistent). BUT it’s certainly sufficient, so I can’t complain too much. I’m able to get things done, make my tests pass, and so on.

The only bug I ran into was in functions that used printf – I spend about 4 hours tracing stack calls, overflows, missing symbols, and so on until I tracked it down – an error that had been fixed in Unity in August but not found its way into Ceedling until December (after I had downloaded it). Otherwise it’s been great.

 

Next time I’ll actually look at some of the testing.