tests/testthat/test-sus_alt.R

In accessrmd: Improving the Accessibility of 'rmarkdown' Documents

# store the current wd in global scope and setwd to tempdir
with(globalenv(), {
  .old_wd <- setwd(tempdir())
})

# dependencies ------------------------------------------------------------

good_img <- tempfile(fileext = ".Rmd")
file.create(good_img)
writeLines(
  "---
lang: en
---
<img src='something' alt='something else'/>",
  con = good_img
)

bad_img <- tempfile(fileext = ".Rmd")
file.create(bad_img)
writeLines(
  "---
lang: en
---
<img src='something' alt='something'/>",
  con = bad_img
)

plac_img <- tempfile(fileext = ".Rmd")
file.create(plac_img)
writeLines(
  "---
lang: en
---
<img src='something' alt='nbsp'/>",
  con = plac_img
)

specdim_imgs <- tempfile(fileext = ".Rmd")
file.create(specdim_imgs)
writeLines(
  "---
lang: en
---
<img src='something' alt='acceptable alt text' height='300' width='300'/> 
<img src='something' alt='spacer' height='300' width='400'/>
  ",
  con = specdim_imgs
)

mixed_imgs <- tempfile(fileext = ".Rmd")
file.create(mixed_imgs)
writeLines(
  "---
lang: en
---
<img src='unacceptable' alt='unacceptable' height='300' width='300'/> 
<img src='alt_is' alt='acceptable' height='300' width='300'/> 
<img src='unacceptable' alt='spacer' height='300' width='400'/>
![acceptable](alt_is)
![nbsp](unacceptable_alt)
  ",
  con = mixed_imgs
)

missing_alt <- tempfile(fileext = ".Rmd")
file.create(missing_alt)
writeLines(
  "---
lang: en
---
<img src='no_alt_included'>
<img src='no_alt_included' alt=''>
![](no_alt_included)
  ",
  con = missing_alt
)

long_alt <- tempfile(fileext = ".Rmd")
file.create(long_alt)
writeLines(
  "---
lang: en
---
![Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.](lorem_ipsum)

<img src=\"lorem_ipsum\" alt=\"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\">
  ",
  con = long_alt
)


# tests -------------------------------------------------------------------

test_that("Messages when no suspicious cases are found", {
  expect_message(
    sus_alt(good_img),
    paste0("Checking ", basename(good_img), "...")
  )
  expect_message(
    sus_alt(good_img),
    "No images with placeholder text found."
  )
  expect_message(
    sus_alt(good_img),
    "No images with equal src and alt values found."
  )
})

test_that("Messages when dupe alt is found", {
  expect_message(
    suppressWarnings(sus_alt(bad_img)),
    paste0("Checking ", basename(bad_img), "...")
  )
  expect_message(
    suppressWarnings(sus_alt(bad_img)),
    "No images with placeholder text found."
  )
  expect_warning(sus_alt(bad_img), "alt text should not be equal to src.")
  expect_warning(
    sus_alt(bad_img),
    "Check lines:
 4"
  )
})

test_that("Messages when placeholder alt is found", {
  expect_message(
    suppressWarnings(sus_alt(plac_img)),
    paste0("Checking ", basename(plac_img), "...")
  )
  expect_message(
    suppressWarnings(sus_alt(plac_img)),
    "No images with equal src and alt values found."
  )
  expect_warning(
    sus_alt(plac_img),
    "alt text should not be empty or equal to 'spacer' or 'nbsp'."
  )
  expect_warning(
    sus_alt(plac_img),
    "Check lines:
 4"
  )
})

test_that("imgs with square specified dims do not get flagged as suspicious", {
  expect_warning(
    sus_alt(specdim_imgs),
    " Check lines:
 5"
  )
})


test_that("Complex case behaves as expected", {
  expect_warning(
    sus_alt(mixed_imgs),
    "Check lines:
 6, 8"
  )
  expect_warning(
    sus_alt(mixed_imgs),
    "Check lines:
 4"
  )
})

test_that("Blank alt is flagged", {
  expect_warning(
    sus_alt(missing_alt),
    " Check lines:
 4, 5, 6"
  )
})

test_that("Long alt text is flagged", {
  expect_warning(
    sus_alt(long_alt),
    "Check lines:
 4, 6 "
  )
})


# set the wd to test directory
with(globalenv(), {
  setwd(.old_wd)
})