Corner case vs. edge case

Corner cases and edge cases are different things even though they are commonly referred to as the same thing.

Let’s formally define both:

• An edge case is an issue that occurs at an extreme (maximum or minimum) operating parameter.

• A corner case is when multiple parameters are simultaneously at extreme levels, and the user is put at a corner of the configuration space.

For the oven, an edge case would be setting the heat power to extreme values, i.e., either 1 or 5.

A corner case would be a situation when multiple parameters are at extreme values. For instance, if both times were set to 10 minutes and the heat power was at 5, or if the time was set to 0.5 minutes and heat to 1.