This is a suggestion from
https://github.com/MangoTheCat/blog-with-mock/blob/master/Blogpost1.Rmd
as a way to test interactive code in unit tests. Basically, in the unit tests,
we use testthat::with_mock
, and inside that we redefine isInteractive
just for the test. In all other times, this returns the same things as
interactive()
.