`skip_if_auto_test`: option to skip some test when using `auto_test()` or `auto_test_package()`

[StatisMike]

I am curently developing a package wrapping around some external REST API. There are a lot of simple tests for objects and requests constructors and response translations which run lightingly-fast and are ideal for auto_test() and auto_test_package(). I think it would be helpful if there was a skip_if helper that would allow skipping longer running tests (in my example: request send and response verification).

Currently I need to add skip() when developing code to all of these longer-running tests (for auto_test_package()) or keep all fast-running tests in different directory (for auto_test()).

Unless there is actually some option for that already - I would suggest adding it to auto_test() documentation.