All the testing for this diff came from its use in D5524. In that diff I was able to implement the action sheet using the flow types I created in this diff, and I received no flow errors which I believe to be a good indicator that everything is correct. I noticed in the [[ https://github.com/flow-typed/flow-typed/blob/master/CONTRIBUTING.md#writing-tests | flow docs ]], there was a section to write tests; however, I also noticed that the other flow-typed library definitions in our code base also don't have any tests, but if this is something we want to get done, I will take a look into it