Why developers avoid writing tests… until it’s too late

Writing tests represents one of those few stages of software development that is usually overlooked, even though it may be one of the most important one. Developers mention it and usually are either uncomfortable and prefer not to write tests for their code, or have many excuses for not writing them at all.

Well, tests are important:

• A software bug in a Therac-25 radiation therapy machine caused the death of five patients after receiving a massive dose of X-rays.
• Knight Capital lost half a billion dollars in half an hour when a software bug allowed computers to sell and buy millions of shares with no human oversight.

These and many other stories tell how seemingly unimportant bugs can actually cause so many tragic disasters.

We know how critical software is becoming to every area of our lives. We know that the security, stability and correctness of this software has a crucial importance in our lives. So the question is: why do developers still avoid writing tests?

Excuse #1: “Writing tests just takes too much time.”