The Origin of Software by Means of Artificial Selection
New video lesson #49 in the Modern Embedded Systems Programming course explores the vast subject of software testing.
The most important takeaway from this lesson is that the only way to create anything complex is to evolve it, and the winners of the software development game are those who evolve the software faster by applying better, smarter, and more effective testing techniques to eliminate more defects sooner.
This software evolution is guided by artificial selection, which requires building artificial environments to test the software.
This lesson gave you an idea about one such artificial environment for unit testing (a unit testing harness), but the general idea is similar for most such harnesses.
Newcomers to unit testing often need clarification as to what exactly is being tested. A first impression might be that testing only concerns the CUT (Code Under Test). But you must realize that all tests necessarily exercise the CUT and the test environment. Therefore, methodologies like Test Driven Development (TDD) recommend starting the process without a CUT. The purpose of this first failing test is really to test the environment.
And finally, when you start testing more systematically, you will accumulate many tests. On the one hand, such tests are valuable for checking that your software keeps working and that the new features don't break the old ones, which is called regression testing. On the other hand, tests are code, too, and the more code you have, the slower you can progress. The trick is to find the right balance and discard the less relevant tests. Keeping all tests forever is a mistake.
I like the new terminology- Artificial environment, if I understand correct we currently call it as unit test environment/infrastructure where we provide simulated inputs for CUT. In today’s embedded world CUT is more important as it integrates into larger systems. Great read.