Testing and TDD

When you write the first lines of some library, it's difficult to introduce many bugs. But once the source code gets bigger and bigger, it becomes easier to break things. The team grows and now many people are writing the same source code, new functionality is added on top of the code that you wrote at the beginning. And code stopped working by some modification in some function that now nobody can track down.

This is a common scenario in enterprises that testing tries to reduce (it doesn't completely solve it, it's not a holy grail). When you write unit tests during your development process, you can check whether some new feature is breaking something older or whether your current new feature is achieving everything expected in ...

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