"Test while developing!" is the Drona creed. Studies have revealed that the sooner problems are detected; the less expensive they are to correct. There are several reasons for this:

The knowledge of that area of the code is still fresh in the developer's mind.

Additional code has not been created that interacts with the code to be changed.

In the worst case, replacing software that has already shipped is very expensive

Before shipping, each milestone receives a complete test by Quality Assurance. Any known bugs uncovered during development and will be assigned Bug Tracking Report (BTR) numbers. The BTR numbers are used to track post-ship defects.

BTRs are released for the following conditions:

•  Module-wise after system testing by customer.
•  Along with the next scheduled software release.
•  Depending on the severity of the defect.