tests/testthat/test-worldclim.R

In climenv: Download, Extract and Visualise Climate and Elevation Data

test_that("worldclim() fails gracefully", {
  expect_error(
    expect_warning(worldclim(var = "stop", res = 1),
                   "Invalid value of `resolution`")
    , "invalid `var`"
  )

  flip_lat_long <- sf::st_as_sf(
    data.frame(lat = c(-72, -73, -73, -72),
               lng = c(-156, -156, -157, -156)), coords = 1:2
  )
  tmp_dir <- tempdir()
  on.exit(unlink(tmp_dir))
  expect_warning(
    expect_null(worldclim(out = tmp_dir, loc = flip_lat_long, var = "prec")),
    "Could not map all coordinates to tiles"
  )
})

test_that("worldclim() downloads data", {
  skip_if_offline() # Requires connectivity
  skip_on_cran() # download is slow

  # CRAN policy: Packages should not write [anywhere] apart from the
  # R session’s temporary directory [...] and such usage should be cleaned up
  tmp_dir <- tempdir()
  on.exit(unlink(tmp_dir))

  # Smallest download available is tile_50_wc2.1_30s_elev.tif: 134K
  # Smallest climate download is tile_50_wc2.1_30s_prec.tif: 407K
  tile50 <- sf::st_as_sf(
    data.frame(lat = c(-59, -59, -58, -59),
               lng = c(-123, -124, -123, -123)), coords = 2:1
  )

  # Obtain raster files
  worldclim(out = tmp_dir, loc = tile50, var = "prec", quiet = TRUE)
  tile_files <- paste0(
    tmp_dir, "/prec/wc2.1_30s_prec_",
    formatC(1:12, width = 2, flag = "0"), ".tif"
  )
  expect_equal(file.exists(tile_files), rep(TRUE, 12))

  # Check data matches expectation
  skip_if(!file.exists(tile_files[1]))
  jan50 <- terra::rast(tile_files[1])
  thumb <- terra::aggregate(jan50, fact = 64)
  expected <- terra::rast(test_path("expected", "jan50.tif"))
  expect_true(all.equal(rast(thumb), rast(expected)))


  # Run this code manually to update the "Expected" value
  if (FALSE) {
    terra::writeRaster(
      thumb, overwrite = TRUE,
      test_path("expected", "jan50.tif")
    )
  }


  # Multiple tiles: spanning 49 & 50 will give smallest download size (~280KB)
  south <- sf::st_as_sf(
    data.frame(lat = c(-59, -59, -58, -59),
               lng = c(-123, -174, -123, -123)), coords = 2:1
  )

  # Obtain raster data
  worldclim(out = tmp_dir, loc = south, var = "elev", quiet = TRUE)
  south_file <- paste0(tmp_dir, "/elev/wc2.1_30s_elev_01.tif")
  expect_true(file.exists(south_file))

  # Check data matches expectation
  south_elev <- terra::rast(south_file)
  thumb <- terra::aggregate(south_elev, fact = 64)
  expected <- terra::rast(test_path("expected", "south_elev.tif"))
  expect_true(all.equal(rast(thumb), rast(expected)))


  # Run this code manually to update the "Expected" value
  if (FALSE) {
    terra::writeRaster(
      thumb, overwrite = TRUE,
      test_path("expected", "south_elev.tif")
    )
  }
})