Ensure verify_output() handles \r correctly

[hadley]

library(testthat)

path <- tempfile()  
verify_output(path, cat("\r\n"))
#> Warning: Creating reference output
verify_output(path, cat("\r\n"))
#> Error: Results have changed from known value recorded in '/tmp/RtmpKf8dbf/file5e0b64a0acc5'.
#> 1/3 mismatches
#> x[2]: "\r"
#> y[2]: ""

^{Created on 2020-06-16 by the reprex package (v0.3.0)}

[hadley]

test_that("verify_output() handles line-feeds", {
  verify_output(test_path("test-verify-conditions-lf.txt"), {
    cat("\r\n")
  })
})