Test breaks in future ggplot2 release

Hi there,

While preparing for a new release of ggplot2, our reverse dependency check showed that one of your package's tests has broken.
In particular, we've updated an error message that seemed to be part of your test here:

xpose/tests/testthat/test-xpose_save.R

Lines 33 to 34 in 8681756

    
           expect_error(xpose_save(plot = plot, file = paths_1), 
        
                        regexp = 'device.+must be.+NULL.+string or a function')

Our suggestion, that might extend to testing any messages originating from other packages, is to replace this test with a snapshot test. You could test any solutions with the current release candidate branch, that can be installed with devtools::install_github('tidyverse/ggplot2@v3.4.1-rc').

We plan to submit the next release of ggplot2 by the end of January, and hope that you might be able to fix the test before then.

Best wishes,
Teun

	expect_error(xpose_save(plot = plot, file = paths_1),
	regexp = 'device.+must be.+NULL.+string or a function')