cotesting

Cotesting, also spelled co-testing, is a collaborative software testing approach in which two or more testers work together on the same testing activities to verify software behavior and quality. It often involves pairing or small groups who design tests, execute test cases, explore the product, and review results in a shared context. Cotesting can be applied throughout a project, from feature discovery to regression checks, and may be combined with automated testing and continuous integration.

In practice, cotesting can take several forms. Pair testing pairs a tester with a developer, product owner, or another tester who alternates driving and observing. Mob testing extends this idea to a larger group. Sessions use shared objectives, charters, or checklists and commonly rely on collaborative exploration, collaborative review of failures, and immediate knowledge transfer. Test artifacts such as test cases, checklists, and issue reports are created and refined collectively, with automation leveraged where appropriate.

The approach offers several benefits. It can increase test coverage and defect detection, reduce knowledge silos, improve communication with developers, and shorten feedback loops in CI/CD environments. It also supports learning and skill development through hands-on collaboration and rapid feedback.

However, cotesting also presents challenges. It requires time and disciplined coordination, can be slowed by personality clashes or unclear goals, and may lead to duplicated effort if not well managed. Success hinges on a clear purpose, facilitator role, and alignment with overall testing strategy. Cotesting is not a universal standard and is often treated as a complementary practice to independent testing and automated verification.