tests/testthat/setup.R

In lewinfox/lambdar: Tools for building AWS Lambda functions in R

# We don't want usethis printing messages during testing because it clutters the console. See
# https://community.rstudio.com/t/how-to-test-functions-that-operate-on-projects-without-cluttering-test-output/113283/2
# for the background
options(usethis.quiet = TRUE)


# Pinched from https://github.com/jimhester/usethis/blob/de8aa116820a8e54f2f952b341039985d78d0352/tests/testthat/helper.R#L28-L68
# See https://github.com/r-lib/devtools/blob/78b4cabcba47e328e255fffa39e9edcad302f8a0/tests/testthat/test-build-readme.R
# for an example of how to use.
create_local_thing <- function(dir = fs::file_temp(),
                               env = parent.frame(),
                               rstudio = FALSE,
                               thing = c("package", "project")) {

  if (!requireNamespace("fs", quietly = TRUE)) {
    rlang::abort("Package `fs` is required but not installed.")
  }

  thing <- match.arg(thing)
  if (dir.exists(dir)) {
    usethis::ui_stop("Target {ui_code('dir')} {usethis::ui_path(dir)} already exists.")
  }

  # I ran into an issue where R CMD check where the old_project (tests/testthat in the temporary
  # folder) was not a project so this `proj_get()` call failed with an error. Wrapping this in a
  # `try()` allows us to A: stop those tests failing and B: check for the existence of an old
  # project before trying to switch back to one below.
  old_project <- try(usethis::proj_get(), silent = TRUE)
  has_old_project <- !inherits(old_project, "try-error")
  old_wd <- getwd()          # not necessarily same as `old_project`

  withr::defer(fs::dir_delete(dir), envir = env)

  switch(
    thing,
    package = usethis::create_package(dir, rstudio = rstudio, open = FALSE, check_name = FALSE),
    project = usethis::create_project(dir, rstudio = rstudio, open = FALSE)
  )

  if (has_old_project) {
    withr::defer(usethis::proj_set(old_project, force = TRUE), envir = env)
  }
  usethis::proj_set(dir)

  withr::defer(setwd(old_wd), envir = env)

  setwd(usethis::proj_get())
  invisible(usethis::proj_get())
}

# Create a local lambdar project with config, runtime and a main.R file containing two handlers
with_local_project <- function(code) {
  withr::with_options(list(lambdar.quiet = TRUE), {
    create_local_thing(thing = "project")
    init()
    main_text <- "
    #' @lambda
    hello_world <- function(name = NULL) {
      if (is.null(name)) {
        name <- 'World'
      }
      paste0('Hello, ' name, '!')
    }

    #' @lambda
    add_one <- function(x = 0) {
      x <- as.numeric(x)
      x + 1
    }
    "
    cat(main_text, file = "main.R")
    force(code)
  })
}