# Difference between Corner Case Testing, Boundary Case Testing and Edge Case Testing

Can someone explain difference between Corner Case Testing, Boundary Case Testing and Edge Case Testing with an example.

• Sure @PDHide. I was waiting for a while if someone can provide more examples. – JAINAM Mar 13 '20 at 6:31
• sure thanks : ) – PDHide Mar 13 '20 at 6:32
• Note that there is no consensus on these terms, besides Boundary Testing. I could think of at least 3 possible definitions for Corner and Edge Testing, including some shared by the two terms. If somebody is using these terms, I would suggest you straightforwardly ask what this person means. – João Farias Mar 14 '20 at 10:44
• Why do I feel like this question was already asked but I can't find it? Ah, it is here: softwareengineering.stackexchange.com/q/125587/3385 – Nakilon Mar 18 '20 at 17:53

Corner Case Testing:

When the system breaks only for a specific valid input

eg:

Imagine a function getcar() that that takes a number and all numbers from 1-5 are valid inputs:

But,

getcar(wheel=?) function works with all numbers but fails for getcar(wheel=3)

Edge Case Testing:

Here we check that the system handles extreme values of valid limits.

For the above example, the valid edge case scenarios are getcar(wheel=1) and getcar(wheel=5)

Boundary Case Testing:

Here we check that the system handles boundary values around the edge case values.

so in the above example, edge case values are 1 and 5. So, the boundary cases would be 0,2,4,6

These 3 are are common terms used in functional testing services and below are the details with example:-

The edge cases are cases whereby there is one condition tested on the extreme ends of possible values.

For simplicity consider a hardware example, a speaker with a volume range from 0 to 10; has edge cases at 0 and 10. Other example like what would happen if a user tries to upload a file with the maximum size allowed.

Corner cases are where multiple edge conditions are involved in testing. In our speaker example, a corner case could be testing volume extremes (like in an edge case) but at the same time test the edge of bass levels