We grabbed the best features of each framework and created what we think it’s the best C++ unit-testing framework out there (for our needs anyway). We took the results and put them up in Sourceforge under a veryunrestrictive license, and that’s how UnitTest++ was born.
I had been using a modified version of CppUnitLite for quite a while, slowly fixing the parts in need of mending, and adding new functionality as it became needed. Eventually I released most of those changes as CppUnitLite2, and I thought that would be the end of that. It turns out that was just the beginning.
Shortly after that, several people started emailing me with new functionality, fixes, patches, suggestions, etc. At the same time, Charles Nicholson was starting to get quite a bit of response as well for his own testing framework, sometimes with similar fixes and suggestions.
If this was going to grow to be a real project, developing over time, supporting users’ needs, and accepting code contributions, clearly it would make sense to join forces. And that’s exactly what we did. We grabbed the best features of each framework and created what we think it’s the best C++ unit-testing framework out there (for our needs anyway).
Our ultimate goal is to apply test-driven development to game development. All of the existing frameworks fell short in one area or another. Specifically, the driving forces behind the design of UnitTest++ are:
- Portability. As game developers, we need to write tests for a variety of platforms, most of which are not supported by normal software packages (all the game consoles). So the ability to easily port the framework to a new platform was very important.
- Simplicity. The simpler the framework, the easier it is to add new features or adapt it to meet new needs, especially in very limited platforms.
- Development speed. Writing and running tests should be as fast and straightforward as possible. We’re going to be running many tests hundreds of times per day, so running the tests should be fast and the results well integrated with the workflow.
UnitTest++ is a fully featured testing framework, with many of the features you may expect from Xunit-style frameworks such as fixtures and reporting. Additionally, here are some of the specific features that make UnitTest++ unique:
- Minimal work required to create a new test. For TDD development, we write lots and lots of tests, so creating a new test should be as quick and painless as possible. UnitTest++ does not require explicit test registrations, and creating new tests requires minimal work.
- Good assert and crash handling. When automated tests are executed, it’s very important not to hang the process or abort the tests any time the program crashes or an assert fails. UnitTest++ will catch and report exceptions as failed tests and print a lot of information about them. It will translate signals to exceptions as well as be able to catch invalid memory accesses and other problems.
- Minimal footprint and minimal reliance on heavy libraries. When you intend to run tests on a Cell SPU with a measly 256 KB of RAM, you really want to be as lean and mean as possible. UnitTest++ is very lightweight, and it will get even lighter weight once strstream is replaced.
- No dynamic memory allocations done by the framework, which makes it much easier to track memory leaks and generally more attractive for embedded systems.
- Multiplatform support. Right now it supports Win32, Linux, and Mac OS X out of the “box,” and other platforms will probably work without any changes. The source code makes use of platform-specific functions whenever necessary, so it is easy to hook up special timers, allocators, or reporters for specific platforms. The code comes with a makefile as well as with project and solution files for Visual Studio 2003 and 2005.
- Full set of unit tests for itself. UnitTest++ was TDD’d from the ground up, including some of the ugly macros (imagine how much fun it was bending the framework to test itself that way!). It goes without saying, all the tests are included with the source code, so you can go totally wild with them 🙂
This was just the first release. UnitTest++ is ready for full production work, but we already have plans beyond this release. This is a peek at some of the features we have in mind for upcoming versions:
- Out-of-the-box support for game console platforms (Xbox 360, PS3 PPU and SPU, and Nintendo Revolution). Of course, this is dependent on us getting permission from the console manufacturers to release some code that works with their SDK.
- Ability to trade some features (such as rich check reporting) for some extra memory. In some platforms, like Cell SPUs, you really need to go barebones.
- Suites to group tests together.
- Different reporters (HTML, GUIs, etc). Don’t worry, all those modules will be optional and well separated, so they won’t affect the simplicity of the framework.
- Per-test timings. Maybe the ability to flag some tests as not exceeding a certain amount of time, or just failing any test that goes over a threshold.
- Built-in memory leak detection.
So that’s it. Download the source code and give it a try. We welcome any comments and suggestions (best channels would be through the project mailing list or comments here). We hope you find it useful and that it makes your TDDing even more productive.