Why Testing?

Learn about the importance of testing.

We'll cover the following

In this lesson, we will discuss the importance of testing.

Reasons

The main reasons for testing are:

To ensure that the code does what we expect now and when we refactor/modify it. Testing protects us from direct regressions when we break the existing code and from indirect regressions when something external from our code breaks it.
To reproduce edge cases in the easiest possible way.
To leverage the speed of an automated tool that performs checks much faster than you could do manually.
To leverage the checks forever, even when it becomes impossible to test everything manually.
To tell a story about the code. It’s easier to maintain test descriptions than documentation. A good storytelling test suite allows everyone to jump into the codebase easily.
To avoid adding temporary and risky code, conditions, default state, etc. by enabling you to test something.
To prevent problems rather than needing to solve them later on.
To allow ourselves to refactor the code without fear of ruining the codebase. A well-tested codebase can be refactored safely.
To improve the quality of the code: a hard-to-test code is indicative of poor design.
To lower your cognitive load. Testing helps you concentrate on your project instead of focusing on everything surrounding it.
To have an objective metric that measures the behavioral correctness of your software.

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