The key for agile is speed. But is fast development enough? Can testing match the speed and iterative nature of agile? And how?
Exploratory Testing provides the best match in the situation. Cutting off the time spent in test design, Exploratory Testing combines learning, test design, and test execution.
In simpler terms, the tester begins exploring the application, and builds the test scenarios on the go, using his experience. The requirements and functionalities are often revealed and validated simultaneously. While this sounds exciting, a lot depends on the ability and skills of the testers, and they need to selected carefully. New testers may struggle without prescribed cases and guidelines, while busy testers may not address all aspects.
Exploratory Testing can focus on incremental feature additions and other aspects not covered in automated testing, so that it complements the formal testing.