It’s often said that a downside of Test Driven Development is it often forces you to expose information related to a class that would of been private if written without Test Driven Development. I wish to provide some food for thought and to tell you this is not true. In fact, if you feel you are being forced to compromise design for testing, it is not the fault of the testing.
Yes, I am telling you that if you are doing this, you are doing it wrong. Having to expose internals for testing is a clear code smell, and a potent one at that. The solution is, instead, to stop and think. Why is the structure of the code forcing you to make this decision? Why are the responsibilities of this class so encompassing that I cannot tell what it is doing as an outside observer? What have I done wrong?
Exposing internals for testing is a code smell, and in a lot of those situations dependency injection is the detergent. If a classes responsibilities are too big (which is fundamentally what this code smell suggests), then breaking those responsibilities down is the most responsible thing the programmer can do.
Quote of the Day
“I never make stupid mistakes. Only very, very clever ones. ”
Merry Christmas and Happy New Year to all! Hope you’ve had a blast over the holidays. I know I have. I went to my first Company Christmas Shindig. It was great, I got to wear a dinner suit and drink from an open bar. What more could I want?
Now, on to the coding! Lately I’ve been using a lot of C#. It’s what we predominately use at work, which explains that one. Naturally, we try to deliver the best quality product possible, and one of the techniques we employ to do so is test driven development. To accomplish this we largely use NUnit as our testing framework and Moq for mocking out implementations of interfaces. And on average this works very well.
Now in my spare time I like to occasionally code. I am not willing to give up a hobby just because it’s also a career. Now, C# is great and all but I like to spread my wings, stretch my legs and explore other languages. And most modern languages have pretty good support for TDD. C++ isn’t a modern language. In programming terms it’s steampunk, Victorian fashions realised with modern designs. It’s unit testing and mocking libraries are not quite so easy to use in a TDD context.
I tried with quite a few, and had some reasonable success with UnitTest++ combined with Google Mock. But they never quite matched my needs or expectations, unfortunately. And as the old saying goes, if your wheel is difficult to attach to your car, build a new wheel. Then burn the car down with it. It’s an interesting saying. And it led to the creation of my latest little project, UnitTest11.
UnitTest11 is a testing and mocking framework written in C++11 to take advantage of the latest features provided by the language. It aims to involve less Macros than previous testing frameworks, and allow for code to be written in a more modern style. It’s based inherently around the concepts of “Given, When and Then” (Arrange, Act and Assert), and allows for tests to be expressed in this BDD-like fashion without always requiring you to be encumbered by the strictness of Behaviour-Driven Development.
The actual assertions are written to mimic the “natural language” constraint model of NUnit, namely they adopt an “AssertThat(Value, Predicate)” format, to allow for greater readability and flexibility.
The mocking framework is designed to allow for verifications to be made after the act, as assertions. This is something many other C++ mocking libraries, such as Google Mock, do not (to the best of my knowledge) provide good or even any support for. And since both are built into one library, they integrate with less discrepancies compared to when the Testing and Mocking libraries are unrelated.
At present if you wish to look at the library, feel free to do so (For the curious, the code is under the MIT licence). I’ve not completely finished development of it, the tests driving the library are still a mixture of the new UnitTest11 style and older UnitTest++ tests used to bootstrap the development. Also not every feature is fully implemented. For example, whilst the actual Mocking classes are present support for quickly and easily creating Mock Classes is still not fully implemented. I’m looking into the best way to accomplish this, but fear the Google Mock way of having a series of Macros for varying numbers of parameters may be the only viable option. That makes me a little sad.
Still, it works and I would hope it effectively proves the concept. And if Unit Testing and TDD in C++ interest you, feel free to check it out and let me know what you think. I’ll most likely post again about it, with actual code examples, sometime in the near future.
Quote of the Day
“Cease dependence on mass inspection to achieve quality. Improve the process and build quality into the product in the first place.”
William Edwards Deming
Well, that’s it. My fears confirmed, time management has killed me. There is no way I’m getting this done in time. I spent too long on the background under-the-hood code, which maybe related to how that’s the part of coding I find the most fun. Which could also explain why I’m on the Platform Team at work. We make the API and let the Application Team worry about the best shade of Cornflower Blue to show the customers. And that’s what I ended with, the start of what could be a solid API but something only tangentially related to a working game.
On the brightside my code is very modular, and I am definitely going to create something properly using a more refined variation on this design at a later date (and the lack of time limit will let me use proper TDD and the like).
If I take part in the next LD, I’ve learnt a lot here and had fun, even if I have nothing to demo by the end of it but a sprite moving around the screen. I learnt from my mistakes and will hopefully have more to show in the future.
Major respect for the other LDers who actually get something done without getting lost in background implementation details, as I did.
If I could do it again, I’d pick a pre-existing “engine” (hate that term) instead of writing my own. I just can’t write fast and hackish code without feeling unclean, but for rolling things yourself I’m not experienced enough to do anything but in the timeframe. I fought against that, and it took me too long.
Also I’d impose a much stricter “sprint” system, planning out from the start goals on an hour-by-hour basis (using hourly iterations) with a set of things that needed doing I could pull from. I tried this by the end, where I started to pick up the pace, but it was too little too late.
Code by the end is on github for the curious.https://github.com/MorleyDev/ld24Evolution
tl;dr – I failed hard, but had a blast doing so.
Reposted from http://www.ludumdare.com/
Hello world and it’s loved ones. I am MorleyDev. I’m an English computer science student currently on a paid internship at an awesome company obsessed with agile development. Yes, I have been indoctrinated in those ways, so this Ludum Dare will be an interesting test for me. I will be streaming via Google Hangouts and Air, so feel free to check that out. I’ll have to put up links as they go online because of how hangouts on air seems to work (don’t think you can have a permanent link to an unstarted Hangout or embed unstarted Hangouts in a web page, unfortunately).
Language: C++ (GCC for the new C++11 features, using the latest nuwen.net build for MinGW to compile on Windows)
Libraries planned on using: Boost, JML, Google Mock, UnitTest++, SFML, Lua
Targeted OS: Windows, maybe Linux if I have time.
Starting code - Well it’s not exactly “code” but I’ve created an Eclipse project with options to help me do some Testing and Cross-Compiling (if it comes to that). I hope. Maybe. It has some empty mains and the like but nothing “game” related so hopefully it’s allowed and nobody will lynch me in my sleep.
Where I’m not too worried – I’m a programmer. I program. I’d like to think the coding in and of itself won’t be too hear-pulling-out-of-head-and-feeding-to-self-difficult. I’d like a challenge sure, but a challenge I can do.
Where I’ll probably fail - My graphical skills are to be compared with a blind monkey drunk off it’s arse, high on every illicit drug known to man and being repeatedly hit over the head with a shovel. The monkey is also dead. I’m not an artist and so my “art” will be simplistic at best and ugly at best.
Where I’m worried I’ll fail – Ideas, obviously. But also time management. I like to test code and such, and so my feedback cycle will need to be a short one. I’ll probably use compile time to make art assets and such to keep my momentum but it’s a big concern for me. Coding on a slow-as-slow netbook last Ludum Dare actually made me ragequit due to the slow feedback cycle, but since now I have my quad-core hyperthreading laptop back from the repairing place that hopefully won’t be an issue. Hopefully.
- MorleyDev (http://morleydev.co.uk/)
Universities love documentation in their Computer Science courses. I once got 100% on a piece of coursework in no short part because I provided 60 pages of documentation. (autogenerated from comments).
Here’s a little tid-bit: Documentation is a dying art. Universities are way behind. Using TDD, with massive function names and tests to document your code and how it should be used, is the way the industry is going, has been going for the last 10 years and continues to be going. Even large parts of game development, often dismissed as “not possible to test drive”, are being test driven (because the dismissers are wrong, and large parts of game programming can be test driven).
But most universities pay a small lip-service to tests and unit testing, it gets mentioned, you write one for your coursework, it vanishes into the great nether. This is wrong.
Computer Science Students are completely unprepared for industry, and the lack of current practices such as Agile Development and Test Driven Design being taught in Universities is definitely one of the reasons for this.
The option placement year is not optional for anyone at University who wants to work as a Software Developer. It’s the only exposure to modern Software Development they’ll get during their time at University. Because the University sure as heck isn’t going to teach them.
Quote of the Day
“By education most have been misled.”
John Dryden, The Hind and Panther, Part III, line 389.