custom testthat expectation to test if 2 syntaxes are equivalent

expect_same_behavior.R

expect_same_behavior <- function(object, expected, ...){
  object_chr <- deparse(substitute(object))
  expected_chr <- deparse(substitute(expected))
  quiet <- purrr::safely(purrr::quietly(identity))
  object   <- eval(substitute(quiet(object)))
  expected <- eval(substitute(quiet(expected)))
  testthat::expect(
    identical(object$result$result, expected$result$result, ...),
    sprintf("`%s` and `%s` don't return the same result.", object_chr, expected_chr))
  testthat::expect(
    identical(object$result$output, expected$result$output, ...),
    sprintf("`%s` and `%s` don't print the same output", object_chr, expected_chr))
  testthat::expect(
    identical(object$result$messages, expected$result$messages, ...),
    sprintf("`%s` and `%s` don't print the same messages", object_chr, expected_chr))
  testthat::expect(
    identical(object$result$warnings, expected$result$warnings, ...),
    sprintf("`%s` and `%s` don't trigger the same warnings", object_chr, expected_chr))
  testthat::expect(
    identical(object$error$message, expected$error$message, ...),
    sprintf("`%s` and `%s` don't trigger the same error", object_chr, expected_chr))
  invisible(NULL)
}

expect_same_behavior(1, 1)
expect_same_behavior(print(1),print(1))
expect_same_behavior(message(1),message(1))
expect_same_behavior(stop(1), stop(1))

expect_same_behavior(1, 2)
#> Error: `1` and `2` don't return the same result.
expect_same_behavior(print(1),1)
#> Error: `print(1)` and `1` don't print the same output
expect_same_behavior(message(1),message(2))
#> Error: `message(1)` and `message(2)` don't print the same messages
expect_same_behavior(stop(1), stop(2))
#> Error: `stop(1)` and `stop(2)` don't trigger the same error