When you go to write code, maybe you already know what you want the code to do, knowing what it should give you as outputs and answers, but you might not know how to go about writing the code itself. In test driven development, you start with writing the tests first, and then trying to pass those tests, slowly as you go. It sounds like a strange approach to it but it is not as bad as it sounds.
In this blog post, Arek Torczuk talks about test driven development, and how it is the best thing that can happen to software development. First, they start off by describing test driven development, where they say it is, simply, a failing phase, a passing phase, and then a refactoring phase. In the failing phase, we create a test that will fail. In the passing phase, we create or write code, minimal code, that will pass the test. In the refactoring phase, we clean up the tests. Typically with coding, you would write the code, and then write tests. However, Torczuk presents some problems with this way of code development, like when to stop writing tests, or when you are sure implementation is finished. With test driven development, they say there are benefits, such as when writing tests, it makes you ask yourself, what do you want the code to do. They say that you should know the answers to these tests before the code is written. They then go on to provide situations where code may be impossible to test, and how test driven development can be used to help that, like using mocking. They provide code examples with these too, to further help visualize solutions. They provide some additional sources at the end of the article in the event you would like to learn more about test driven development.
This is a strange way to write code, and for those used to writing code before everything else, this can be a difficult adjustment. Personally, I found it fairly difficult to start, but afterwards I was able to write the tests, and then write the code to pass those tests, and then keep doing that. The tests do provide a build up of the code, instead of doing everything all at once, which was what Torczuk was trying to get at with his blog post. It allows the tests to provide the framework of the code and lay it out.
From the blog CS@Worcester – Cao's Thoughts by antcao and used with permission of the author. All other rights reserved by the author.