What is Regression Testing? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what is regression testing

Direct Answer

Regression testing is the process of re-running previously passed tests after code changes to verify that the changes have not broken existing functionality. Regression tests ensure that new features or bug fixes have not accidentally introduced new bugs in previously working parts of the software.

Regression-testing in the UK

Regression testing has direct UK compliance value. Cyber Essentials: when applying security patches within the 14-day window, regression testing ensures the patch doesn't break existing functionality (a common risk with major dependency updates). FCA operational resilience: regression test suites are evidence of systematic quality control for changes to production financial systems. NHS DSP Toolkit: documented regression testing demonstrates mature change management for clinical software. ClickMasters maintains regression test suites for all ongoing maintenance retainer clients — every deployment is preceded by automated regression testing.

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