1.5.2 Tester’s and Developer’s Mindsets

Developers and testers often think differently. The primary objective of development is to design and build a product. As discussed earlier, the objectives of testing include verifying and validating the product, finding defects prior to release, and so forth. These are different sets of objectives which require different mindsets. Bringing these mindsets together helps to achieve a higher level of product quality.

A mindset reflects an individual’s assumptions and preferred methods for decision making and problemsolving. A tester’s mindset should include curiosity, professional pessimism, a critical eye, attention to detail, and a motivation for good and positive communications and relationships. A tester’s mindset tends to grow and mature as the tester gains experience.

A developer’s mindset may include some of the elements of a tester’s mindset, but successful developers are often more interested in designing and building solutions than in contemplating what might be wrong with those solutions. In addition, confirmation bias makes it difficult to become aware of errors committed by themselves.

With the right mindset, developers are able to test their own code. Different software development lifecycle models often have different ways of organizing the testers and test activities. Having some of the test activities done by independent testers increases defect detection effectiveness, which is particularly important for large, complex, or safety-critical systems. Independent testers bring a perspective which is different than that of the work product authors (i.e., business analysts, product owners, designers, and developers), since they have different cognitive biases from the authors.