- it improves the reliability, quality and performance of software;
- helps a developer to check if the software works properly;
- helps to understand the difference between the actual and the expected result, what ensures the quality of the product.
By making software testing a part of programming, developers have the ability to fix bugs at an early stage of development. This reduces the risk of defects in the finished product. If bugs are found at the entry-level, the developer can create reliable software. Thus, the earlier the process starts, the earlier errors are discovered and the lower the cost of fixing them.