Wednesday, January 27, 2021

Interpreting the Regression Test Activity Graph

We just completed a 1.5 week intensive manual regression test phase where we executed almost the complete set of all (several hundreds) test cases. We are in a lucky situation. Our documented test cases represent nearly 100% of all implemented features. If we achieve a 70-80% test coverage, then we get a real good picture of the overall quality of the product increment. That means, aside from the many automated tests, it's worth from time to time, doing some manual end-to-end regression testing.

While tracking the regression testing progress using a cloud based test case management tool, we were looking at the activity graph and it made us smile. It's exactly what we expected.

At the beginning, testers focus executing those test cases that are well documented, having clear instructions and which rely on previously well prepared test data. I mean, objects that are in specific states where testers can execute just the transition from one state to the next and not worry about the laborious setup steps.
Then, testers switch to more complex test cases which take a little more time to understand and test.  This is when the progress curve reaches the peak and progress starts to slow down.
Of course, we also find anomalies. Bugs can slow you down because analyzing and understanding where and when defects were introduced takes additional time. After a few days, the first bugfixes are delivered, too. Developers require your attention to test their fixes. This interrupts testers from working on their suite. The rate of passed tests is decreasing, but still decreasing in a constant and expected way.
In parallel, developers are working already on the next generation of the product, meaning, their user stories get shipped and require testing too. The tester's brain is now busy with a lot of context switching; clearly more than at the beginning of the sprint.
Now that we are more than half way through, we switch to the monster test cases. I call them like that because they do not consist of simple steps, they contain several tests expressed in tables of inputs and expected outputs. That's why I think it's nonense to talk about the number of test cases. A test case can be atomic and executed in seconds, yet another test case can keep you busy for half an hour and more.

Some of the test cases may be poorly documented and require maintenance or correction. Some test cases require the help of a domain expert. The additional information gained should be documented in the test suite, so we don't have the same questions next time. These are all activities running in parallel.

Last but not least, weekend is getting closer. The first enthusiasm is gone, you're starting to get bored.
You hear music from your neighbour. The caf├ęteria gets louder. The sound of clinking glasses reaches your desk. It's time for a break, time to reboot your brain. TGIF! And now it's weekend time!
And then, Monday is back! It's time for another final boost and time to say thank you. Great progress.
We made it Yogi! 
....and I like that graph.


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