tests/testthat/test-utils.R

In decryptr/captcha: Solve Text on Image Computer Vision Challenges

test_that("print captcha as expected", {
  # skip if running in knitr context
  testthat::skip_if(isTRUE(getOption('knitr.in.progress')))
  f_captcha <- test_path("examples/tjpe.png")
  captcha <- read_captcha(f_captcha)
  expect_snapshot(print(captcha))

})

# from the testthat documentation
save_png <- function(code, width = 400, height = 400) {
  set.seed(42)
  path <- tempfile(fileext = ".png")
  grDevices::png(path, width = width, height = height)
  on.exit(dev.off())
  code
  path
}

test_that("plot captcha as expected", {

  skip_on_ci()
  skip_on_cran()

  f_captcha <- test_path("examples/tjpe.png")
  captcha <- read_captcha(f_captcha)

  expect_snapshot_file(save_png(plot.captcha(captcha)), "plot.png")
})

test_that("plot captcha as expected, big images", {

  skip_on_ci()
  skip_on_cran()

  f_captcha <- rep(test_path("examples/tjpe.png"), 110)
  captcha <- read_captcha(f_captcha)
  expect_message(
    expect_snapshot_file(save_png(plot.captcha(captcha)), "plot_many.png"),
    "Too many"
  )
})

test_that("plot captcha with annotation", {

  skip_on_ci()
  skip_on_cran()

  if (check_magick_ghostscript(error = FALSE)) {
    f_captcha <- test_path("examples/tjpe_4wba3.png")
    captcha <- read_captcha(f_captcha)
    expect_snapshot_file(save_png(plot.captcha(captcha)), "plot_annotation.png")
  } else {
    expect_error(check_magick_ghostscript())
  }

})

test_that("subset and length works", {

  f_captcha <- rep(test_path("examples/tjpe.png"), 10)
  captcha <- read_captcha(f_captcha)

  captcha_subs <- captcha[1:4]

  expect_length(captcha, 10)
  expect_length(captcha_subs, 4)
  expect_equal(length(captcha), 10)
  expect_equal(length(captcha_subs), 4)
})