Agile software testing is part of the Agile Manifesto written in 2001. The authors sought to emphasize practicality and flexibility over rigidly adhering to a project plan. The Agile model for either development or testing places greater value on responding to the user’s needs than following the terms of the contract. The main theme is collaboration, interaction, and flexibility rather than achieving specific milestones tied to rigid deadlines.

The traditional testing scenario involves testing the code to be sure it performs as written. Agile testing takes into account what the user needs and the code to accomplish for them. The code may be written exactly according to the project plan and function flawlessly, but there is little value if the output is not useful from the customer’s prospective. Traditional testing usually occurs following the completion of a major milestone in the development plan while agile testing is ongoing and iterative.

Agile testing is usually done in conjunction with agile development. New code is written in response to customer needs or specific requests. New code may be written to correct a specific bug. In either case, the new code is tested as soon as the developers feel it is stable enough. Once testing is completed, including regression testing, a new iteration of the code can be deployed to meet the customer’s needs sooner than under the traditional coding/testing model.

Agile development and testing have gained significant popularity due to the improved delivery times and continuous integration of new features or bug fixes.