With the exception of the most basic programs, no software exists without faults in some form or another. It's important that your software is tested thoroughly enough to ensure that there are no faults that affect performance to a point where the software is considered to be a liability or unreliable. A large part of reliability comes from the strategy for testing the software, with good strategies making the difference between discovering serious faults and them going unnoticed.
Some considerations for how software is tested during and upon completion of the project should include:
Testing effort consideration - The effort required for testing will grow in proportion to the size of the project. As more features are added to the software system, more testing will be required to test each of them for every version update. Even where features haven't been altered in the new release, a thorough testing strategy should ensure that all features are tested prior to a new release...