Summary:
We suspect that we have some error in diffing algorithm that cause some crashes in mounting layer, so we decided to write a comprehensive unit tests for that.
Writing them we realized that it would be cool to also enable that for normal app run in the debug more, so we can catch the problem in real environment when/if it happens.
Reviewed By: mdvacca
Differential Revision: D14587123
fbshipit-source-id: 6dcdf451b39489dec751cd6787de33f3b8ffb3fd