expect_silent()

[hadley]

i.e. no output, warnings, messages or errors.

[mmaechler]

I was looking for expect_no_message() and expect_no_warning() which are a bit more fine grained than just "silent". Also, I'd expect errors to trigger anyway, so there's no need to mention them here (or in the new functionality code).

[pitakakariki]

I'd expect everything I test to be silent. I wonder if there's a way of implementing this that doesn't have nearly every test basically duplicated?

expect_equal(f(), 42)
expect_silent(f())

[hadley]

I think would just test for absence of warnings, messages and output, since errors should be handled otherwise. Messages and output are usually ignored, and warnings will bubble up (once #254) is fixed.

@mmaechler this would be in addition to #219