Chapter 4 – Test Analysis & Design
Mutation Testing – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
A method to determine test suite thoroughness by measuring the extent to which a test suite can distinguish the program from slight variants (mutants) of the program.
In simple words
Automatically tweak the code in tiny ways and check whether your tests catch each change — if not, tests are weak.
Exam tip
Mutation testing measures test quality, not code quality — kill ratio is the key metric.
Related terms
- Test AutomationLetting tools do the repetitive parts of testing — usually execution, but also data generation and reporting.
- Code CoverageThe percentage of code your tests actually run — measured at statement, branch or condition level.
- White-Box TestingYou design tests using knowledge of the code — branches, statements, paths — to hit specific structural coverage targets.
Practice this term in the ISTQB Mock Test
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