Regression Testing Clarified

Regression testing needs to be automated and run in a Continuous Testing server multiple times a day.

Zhimin Zhan
10 min readOct 4, 2021


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This article is one of the “IT Terminology Clarified” series.

Between 2010–2013, I spoke at a few international software testing conferences (and decided no more, see reasons here). Quite commonly, there were pre-attendance surveys on the attendants’ interested topics. From my memory, the top three (the order might vary) were the same.

  • Test Automation (End-to-End)
  • Regression Testing
  • Web App Testing

However, topics on regression testing were rare at software testing conferences. Several attendants told me this at different events (after attending mine).

In this article, I will share my thoughts and experience in regression testing. This article is a bit long, with the following sections:

  • What is Regression Testing?
  • Status of Regression Testing in Software Projects (quite sad)
  • Regression Testing must be automated, however, …
  • Manual Regression Testing is Evil in Agile
  • How often do you do regression testing? (correct answer: multiple times a day)
  • How long should full regression testing take? (correct answer: about 30 minutes)
  • Why don’t software teams do automated regression testing?

For readers who are interested in the implementation, check out this article: How to Implement Real Automated Regression Testing?

1. What is Regression Testing?

Regression Testing in software means “re-running functional and non-functional tests to ensure that previously developed and tested software still performs after a change (Wikipedia). Every software team member understands the objective of regression testing, as we often see regression errors. However, not many software engineers (including testers) understand how to do regression testing properly.



Zhimin Zhan

Test automation & CT coach, author, speaker and award-winning software developer. Help teams succeed with Agile/DevOps by implementing real Continuous Testing.