Unit testing

It is generally agreed that writing bug-free software is impossible, especially when your code runs on third-party hardware, such as a mobile phone, and has to interact with users, who can (and will) do all kinds of unexpected things.

However, for some situations, such as reusable function libraries, the requirements can be well defined, and the data inputs known in advance. In these situations, not only is a strong set of tests a great way to ensure the library is as bug-free as possible, but it also allows you to make changes to the code (for example, performance improvements, memory optimizations), knowing that your changes have not affected the expected behavior of the library.

Unit tests are one of the things that can help us to write modular, efficient, and bug-free code. The unit test is not the only way of testing code, of course, but it's a crucial part of testing small pieces of software in a manner that isolates it from other parts, helping us to...