tests/testthat/test-extract.R

In lightson: Download and Analyse Nighttime Lights Satellite Data

test_that("extract_panel returns correct structure", {
  r1 <- make_raster(vals = rep(10, 100))
  r2 <- make_raster(vals = rep(20, 100))
  rasters <- list("2020" = r1, "2021" = r2)
  polygons <- make_polygons()

  result <- extract_panel(rasters, polygons, id_col = "region_id")

  expect_s3_class(result, "data.frame")
  expect_named(result, c("region_id", "year", "mean_radiance", "n_pixels"))
  expect_equal(nrow(result), 6L) # 3 regions × 2 years
  expect_type(result$region_id, "character")
  expect_type(result$year, "integer")
  expect_type(result$mean_radiance, "double")
})

test_that("extract_panel errors on unnamed rasters list", {
  r <- make_raster()
  polygons <- make_polygons()
  expect_error(extract_panel(list(r), polygons), "named list")
})

test_that("extract_panel errors on empty rasters list", {
  polygons <- make_polygons()
  expect_error(extract_panel(list(), polygons), "non-empty")
})

test_that("extract_panel years in output match raster names", {
  rasters <- list("2019" = make_raster(), "2022" = make_raster())
  result <- extract_panel(rasters, make_polygons(), id_col = "region_id")
  expect_equal(sort(unique(result$year)), c(2019L, 2022L))
})

test_that("extract_panel supports monthly and daily ISO-date names", {
  rasters <- list("2025-01-01" = make_raster(), "2025-02-01" = make_raster())
  result <- extract_panel(rasters, make_polygons(), id_col = "region_id")
  expect_named(result, c("region_id", "date", "year", "mean_radiance", "n_pixels"))
  expect_s3_class(result$date, "Date")
  expect_equal(sort(unique(result$date)), as.Date(c("2025-01-01", "2025-02-01")))
  expect_equal(unique(result$year), 2025L)
})

test_that("extract_panel rejects mixed annual and dated raster names", {
  rasters <- list("2024" = make_raster(), "2025-01-01" = make_raster())
  expect_error(extract_panel(rasters, make_polygons(), id_col = "region_id"), "either all")
})