tests/testthat/test-gistar.R

In mpjashby/sfhotspot: Hot-Spot Analysis with Simple Features

data_sf <- head(memphis_robberies, 1000)
counts <- count_points_in_polygons(
  points = data_sf,
  polygons = sf::st_set_geometry(create_grid(data_sf), "random_geom_column")
)

# To speed up the checking process, run the function with arguments that should
# not produce any errors or warnings
result <- gistar(counts = counts, n = n)


# CHECK INPUTS -----------------------------------------------------------------

# Note that only inputs evaluated in `hotspot_kde()` are tested here; those
# evaluated in helper functions are tested in the test files for those functions


## Errors ----

test_that("error if `data` is not an SF object", {
  expect_error(gistar(counts = sf::st_drop_geometry(counts), n = n))
})

test_that("error if `n` is not a column in `data or is not numeric`", {
  expect_error(gistar(counts = counts, n = m))
  expect_error(gistar(counts = counts, n = geometry))
})

test_that("error if inputs don't have correct types", {
  expect_error(gistar(counts = counts, n = n, nb_dist = character()))
  expect_error(gistar(counts = counts, n = n, cell_size = character()))
  expect_error(gistar(counts = counts, n = n, include_self = character()))
  expect_error(gistar(counts = counts, n = n, p_adjust_method = 1))
  expect_error(gistar(counts = counts, n = n, quiet = character()))
})

test_that("error if inputs aren't of length 1", {
  expect_error(gistar(counts = counts, n = n, nb_dist = 1:2))
  expect_error(gistar(counts = counts, n = n, cell_size = 1:2))
  expect_error(gistar(counts = counts, n = n, include_self = c(TRUE, FALSE)))
  expect_error(gistar(
    counts = counts,
    n = n,
    p_adjust_method = stats::p.adjust.methods[1:2])
  )
  expect_error(gistar(counts = counts, n = n, quiet = c(TRUE, FALSE)))
})

test_that("error if values are of the correct type/length but are invalid", {
  expect_error(gistar(counts = counts, n = n, nb_dist = -1))
  expect_error(gistar(counts = counts, n = n, cell_size = -1))
  expect_error(
    gistar(counts = counts, n = n, p_adjust_method = "some other method")
  )
})



# CHECK OUTPUTS ----------------------------------------------------------------


## Correct outputs ----

test_that("function produces an SF tibble", {
  expect_s3_class(result, "sf")
  expect_s3_class(result, "tbl_df")
})

test_that("output object has the required column names", {
  expect_equal(sort(names(result)), c("geometry", "gistar", "n", "pvalue"))
})

test_that("columns in output have the required types", {
  expect_type(result$n, "double")
  expect_type(result$gistar, "double")
  expect_type(result$pvalue, "double")
  expect_true(sf::st_is(result$geometry[[1]], "POLYGON"))
})

test_that("column values are within the specified range", {
  expect_true(all(result$n >= 0))
  expect_true(all(result$pvalue >= 0))
  expect_true(all(result$pvalue <= 1))
})