Is there a design pattern that accounts for phone protector/cases

So, I'm wondering if there is a design pattern that counts for the usage of a phone protector/case.

Recently I noticed a new employee use an application we just launched, he was using a protector/case around his phone. This limited the space you could use just by a small bit. However this small bit had a fairly large impact on the slider usage, it just became a bit uncomfortable to select the last option.

So my question is, is there a design pattern for the use of phone protectors/cases or do you just manually test it (To be honest it never occurred to me to include this in my designs)