Catch the error in testthat but dont stop the loop - testing

I have written a package recently and I would like to test few functions where the functions delivers a data.frame when the input is correct, if not it delivers the input as a file into an error folder and logs into a log.log file.

Now the question is: How can i report this movement and do a test that the functions are moving the files into the error folder in test_that?

Thank you!