Software testing consists of a number of different types of tests. These can easily be confused due to their resemblance and seemingly overlapping purposes.
Retesting and regression testing are two commonly confused concepts. They sound alike, and they have similarities too.
The main difference is that regression testing is designed to test for bugs you don't expect to be there, whereas retesting is designed to test for bugs you do expect to be there.
There's more to it than that though, so let's go into further detail to clarify the meaning of these concepts.
The verb regress means to return to a former state or condition. In software, this usually isn’t considered a good thing.
That is why software developers test for regressions, hence the term regression testing. The point of regression testing is to ensure that new updates or features added to software don’t break any previously released updates or features.
To perform regression testing you typically have a regression suite – a series of test cases set up to test these older features.
Regression test cases are often automated because these tests build up as the software changes or grows.
Where retesting differs from regression testing is that, instead of being designed to search through all the previous updates and features of the software to find unforeseen defects and bugs, retesting is designed to test specific defects that you’ve already detected (typically during your regression testing).
In other words, regression testing is about searching for defects, whereas retesting is about fixing specific defects that you’ve already found.
They can therefore occur in one and the same testing process, where:
Read The Ultimate Guide to Test Automation to learn more about different types of tests and how to automate them.
You could say that regression testing is a type of retesting. Retesting essentially means to test something again. And when you are regression testing, you’re testing something that you’ve tested numerous times before.
But determining what the two have in common might confuse more than it will help. So for the sake of clarity, here’s an overview of the key differences.
|Involves testing a general area of the software.||Involves testing a specific feature of the software.|
|Is about testing software which was working, but now, due to updates, might not be working.||Is about testing software which you know was not working, but which you believe to have been fixed. You test it to confirm that it is now in fact fixed.|
|Is ideal for automation as the testing suite will grow with time as the software evolves.||Is not ideal for automation as the case for testing changes each time.|
|Should always be a part of the testing process and performed each time code is changed and a software update is about to be released.||Is only a part of the testing process if a defect or bug is found in the code.|
Make sure to watch our webinar on regression testing at speed to learn more. Or, check out our whitepaper on the topic to learn more about regression testing in agile teams.