Web applications should be tested at presentation, business logic and data layers and within each layer a number of different testing activities should be performed. This includes layer-specific techniques, for example checking for broken links or data recovery possibilities, as well as common techniques like code inspection and black box testing for pre-determined test cases. Discovered errors should be fixed as soon as possible and the testing should continue until no more errors are found. In addition to this, a higher order testing should be undertaken to see if “big picture” requirements are satisfied, and load testing should help to verify application performance and behaviours under heavy user load.