testex
provides a multi-tiered API, allowing you to
adopt it at in a way that makes the most sense for your package –
whether you’re minimizing your dependency footprint or rely on a
specific set of tools. Whatever your workflow, testex
has
something to offer.
Base building-blocks
R examples can include test code! Even if you’re not using
testex
, you can already add tests to your examples!
Here we use .Last.value
to grab the result of our last
example and test it against an expected value. Though, as you might
expect, you can’t easily add another test because
.Last.value
will have changed.
testex
provides a familiar interface for managing just
this:
\examples{
identity("hello, world")
\testonly{testex::testex(
is.character(.),
. == "hello, world")
)}
}
Already testex
is doing a bit of work to make our lives
easier. The .Last.value
is propagated to each of the tests
and we can use the convenient shorthand .
to refer to the
value we want to test.
Use a roxygen2
tag!
If you’re already using roxygen2
, then things get even
easier! roxygen2
can make use of new tags provided by
testex
:
#' Hello, World!
#'
#' @examples
#'
#' hello("World")
#' @test "Hello, World!"
#'
#' hello("darkness my old friend")
#' @test grepl("darkness", .)
#'
#' @export
hello <- function(who) {
paste0("Hello, ", who, "!")
}
After running roxygen2::roxygenize()
, you can take a
peak at the Rd
files and see how the code has been
translated to testex
tests.
Leverage testthat
expectations
A convenience tag is also provide for those that prefer the
testthat
style of testing. testthat
provides a
wealth of expectation functions, which can be used in conjunction with
testex
to write more familiar tests.
#' Hello, World!
#'
#' @examples
#'
#' hello("World")
#' @testthat expect_equal("Hello, World!")
#'
#' hello("testthat my old friend")
#' @testthat expect_match("testthat")
#'
#' @export
hello <- function(who) {
paste0("Hello, ", who, "!")
}
The @testthat
tag will automatically insert the
.Last.value
from the previous example into the first
argument of each expectation. Multiple consecutive
@testthat
expectations will all test the previous example
output.