Using with_output_sink() causing unit tests to fail

[mwmclean]

SWIM has some unit tests that loop over combinations of argument values for a function and call a print method and just check that no errors are thrown. The printing causes a bunch of output I don't particularly want to appear on the console when I use testthat::test_file() and also creates a bunch of output in the travis-CI log files I don't want either. I was hoping I could use with_output_sink() to still run the tests, but without all the annoying output. Unfortunately, this causes an error in a very innocuous looking part of the code that I can't reproduce if I remove the call to with_output_sink(). The test file is here.

[mwmclean]

I fixed this by moving the call to with_output_sink() outside the loop.