Agile Insider reality bytes…

Keeping It Simple – Regression vs Acceptance Testing

Another emergn coach asked me the other day how I distinguished between an acceptance test and regression tests.  For me there is a very simple rule...

• If I write the test before I write any code, it's an acceptance test.
• If I write the test after I've written the code, it's a regression test.
• If I write code to make an acceptance test pass, it is now a regression test.

Keeping it as simple as this keeps you out of trouble, I've seen so many people try to retro-fit acceptance tests after they've written code only to write a test which is based on what they've written rather than what they should have written.  It's a subtle but important point that writing a test for stuff you've written (which might be wrong since you haven't got an acceptance test) means you are potentially writing a test that the system always does the wrong thing...