Exploratory Testing

[thiruvasagamani]

Test Styles/Types and Test Qualities

Exploratory Testing

Exploratory testing is "any testing to the extent that the tester actively controls the design of the tests as those tests are performed and uses information gained while testing to design new and better tests" (Bach 2003a).

Bach points out that tests span a continuum between purely scripted (the tester does precisely what the script specifies and nothing else) to purely exploratory (none of the tester's activities are pre-specified and the tester is not required to generate any test documentation beyond bug reports). Any given testing effort falls somewhere on this continuum. Even predominantly prescripted testing can be exploratory when performed by a skilled tester.

"In the prototypic case (what Bach calls "freestyle exploratory testing"), exploratory testers continually learn about the software they're testing, the market for the product, the various ways in which the product could fail, the weaknesses of the product (including where problems have been found in the application historically and which developers tend to make which kinds of errors), and the best ways to test the software. At the same time that they're doing all this learning, exploratory testers also test the software, report the problems they find, advocate for the problems they found to be fixed, and develop new tests based on the information they've obtained so far in their learning." (Tinkham & Kaner, 2003)

An exploratory tester might use any type of test--domain, specification-based, stress, risk-based, any of them. The underlying issue is not what style of testing is best but what is most likely to reveal the information the tester is looking for at the moment.

Exploratory testing is not purely spontaneous. The tester might do extensive research, such as studying competitive products, failure histories of this and analogous products, interviewing programmers and users, reading specifications, and working with the product.

What distinguishes skilled exploratory testing from other approaches and from unskilled exploration, is that in the moments of doing the testing, the person who is doing exploratory testing well is fully engaged in the work, learning and planning as well as running the tests. Test cases are good to the extent that they advance the tester's knowledge in the direction of his information-seeking goal. Exploratory testing is highly goal-driven, but the goal may change quickly as the tester gains new knowledge.