I want to test in R if a function
For that, I created a reproducible example. There a two scripts, the first one (e.g. test-warning-and-result.R) works fine and without any errors:
library(testthat)
f <- function(x) {
if (x < 0) {
warning("*x* is already negative")
return(x)
}
-x
}
test_that("warning and result", {
x = f(-1)
expect_that(x, equals(-1))
expect_warning(f(-1), "already negative")
})
However, when I run the tests from an external script (e.g. run-test.R), it logically throws a warning at "x = f(-1)"
library(testthat)
test_dir(".")
Since I know there will be a warning and am testing for it, I'm searching for a way to omit the warning within test_that() from the test report. Ideally, I would not have to run the function twice but in one test.
Any Ideas would be appreciated
Ok after having one night's sleep on it I found a simple sollution:
Don't store the functions result in a variable x. Nest the two tests into each other, with the expect_warning outside
Change from
test_that("warning and result", {
x = f(-1)
expect_that(x, equals(-1))
expect_warning(f(-1), "already negative")
})
to
test_that("warning and result", {
expect_warning(expect_that(f(-1), equals(-1)), "already negative")
})