In jackwasey/jwutil: Tools for Data Manipulation and Testing

suppressPackageStartupMessages(library(jwutil, warn.conflicts = FALSE))
suppressPackageStartupMessages(library(testthat, warn.conflicts = FALSE))

cat(packageDescription("jwutil")$Description)

Stress and Fuzz testing

jwutil has some minimal features to allow fuzz and stress testing functions. This is a complicated topic, but at a minimum, the following functions allow you to to give enexpected input to a function, with the expectation it should still work. The packge \code{fuzzr} does more, but does different things.

Extreme integers

Maximum magnitude positive and negative doubles and integers

extreme_numbers

There are several types of zero in R (excluding string representations):

zeroes
sapply(zeroes, class)

Permuting

If the order of arguments in a function should not matter, the result should be the same each time. expect_that_comabine_all_args tests this.

expect_that_combine_all_args(sum(1, 2), testthat::equals(3))

is equivalent to

expect_that(sum(1, 2), testthat::equals(3))
expect_that(sum(2, 1), testthat::equals(3))

This becomes more interesting with named arguments, where the order also should not matter. Beware of testing features of R, rather than your code: R has a complicated but standard way of matching arguments, described in Writing R Extensions. If your function does complicated argument manipulation, and maybe uses ..., this function could verify that named argument order doesn't matter.

res <- gsub(pattern = "the", replacement = "le", x = "Pierre the chat")
expect_that_combine_all_args(
  gsub(pattern = "the", replacement = "le", x = "Pierre the chat"),
  testthat::equals(res)
  )

For functions where the first argument is a vector, and the order of elements in the vector should not matter, expect_that_combine_first_arg will permute all combinations of the first argument, and expect the same result. A large number of elements will take a very long time, factorial with the number of items.

expect_that_combine_first_arg(sum(c(-1, 0, 1)), testthat::equals(0))

Other

lsf lists all the functions in a package, which may be useful to start an attack on all functions with a range of absurd data, looking perhaps for crashes in C/C++ code rather than R errors.