Software testing
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| Note There’s already the test_suite in flightgear/test_suite using CppUnit, thanks to some hard work by Edward. We need more tests written for it, submissions welcome. (Pick an area of interest)[1] |
A well tested piece of software will have a much lower bug count/load. An extensive test suite with unit tests, system/functional tests, GUI tests, installer tests, and other categories of tests can significantly help in this regard.
The benefits of not just chasing clear "wins" are great: An awesome learning experience for new developers; the ability to catch latent, unreported bugs; making it easier to refactor current code by creating a safety net; making it easier for current developers to accept new contributions (when accompanied with passing tests); helping other test writers by contributing to the common test suite infrastructure; and being able to easily check for memory leaks or other issues via Valgrind.[2]
If you are a new developers, just jump in and write any test! It does not need to catch a bug. Do whatever how ever you wish! Just dive in this shallow end and you'll see that the water is not cold.
Writing a test as a safety net. You write the test to pass, make your changes, then make sure that the test still passes. Then you push both the test and core changes.[3]
Benefits of unit testing
There are lots of benefits to writing tests that pass.
Benefits include :
- Learning! New developers can learn a ton from writing a number of passing tests in the area they are interested in. This is one of the quickest ways to learn about a pre-existing and mature code base. You have zero worries about breaking things. This is diving in the shallow end.
- Latent bug uncovering. For every ten tests you write expecting them to pass, one will probably fail. Or at least uncover unexpected behavior that can be improved.
- Refactoring. If we had 10,000 passing tests (assuming universal test coverage), large scale refactoring of the entire code base would be quick and reliable. It would enable refactoring on a scale currently unimaginable. I cannot emphasize enough how much of a benefit this would be.
- Developer turnover. Again if we had 10,000 passing tests (assuming universal test coverage), it would encourage new developers. This is because the fear of breaking something is removed. It is a total safety net. It also would give existing developers peace of mind when a new developer is touching one of the dark parts of FlightGear that no current developer understands (there are plenty of those) .
- Test suite infrastructure. The more passing tests written, the better the test suite infrastructure will become. We can already do a lot. But the addition of more passing tests will help other test writers.
- Memory checking. Running a single test through Valgrind is amazing. Running FlightGear through Valgrind is close to impossible. Passing tests can be written to catch memory leaks!
- Low code quality and standards. This is related to the learning point. As long as a test compiles on all OSes without warning, it passes, and Valgrind gives you an ok, it is good enough. You dont need to be a C++ expert to dive into this shallow end of the pool.
References
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