test_that("they output logical vectors whose lengths match input lengths", {
  expect_vector(middle(1:10), logical(), 10)
  expect_vector(upper(1:11), logical(), 11)
  expect_vector(lower(1:10), logical(), 10)
})


test_that("lower and upper mark 5% of their respective positions by default", {
  expect_identical(lower(1:1000), c(rep(TRUE, 25), rep(FALSE, 975)))
  expect_identical(upper(1:1000), c(rep(FALSE, 975), rep(TRUE, 25)))
})


test_that("middle and tails mark the middle 95% of the data by default", {
  expect_identical(middle(1:1000), c(rep(FALSE, 25), rep(TRUE, 950), rep(FALSE, 25)))
  expect_identical(tails(1:1000), c(rep(TRUE, 25), rep(FALSE, 950), rep(TRUE, 25)))
})


test_that("upper, lower, tails, and middle take variable proportions", {
  expect_identical(lower(1:5, .2), c(TRUE, FALSE, FALSE, FALSE, FALSE))
  expect_identical(middle(1:5, .2), c(FALSE, FALSE, TRUE, FALSE, FALSE))
  expect_identical(tails(1:5, .2), c(TRUE, TRUE, FALSE, TRUE, TRUE))
  expect_identical(upper(1:5, .6), c(FALSE, FALSE, TRUE, TRUE, TRUE))
})


test_that("upper, lower, tails, and middle are greedy for when the cutoff is not clean", {
  expect_identical(lower(1:5, .3), c(TRUE, TRUE, FALSE, FALSE, FALSE))
  expect_identical(middle(1:5, .3), c(FALSE, TRUE, TRUE, TRUE, FALSE))
  expect_identical(tails(1:5, .3), c(TRUE, FALSE, FALSE, FALSE, TRUE))
  expect_identical(upper(1:5, .7), c(FALSE, TRUE, TRUE, TRUE, TRUE))
})


test_that("the values do not need to be pre-arranged", {
  expect_identical(lower(c(2, 1, 3, 4), .25), c(FALSE, TRUE, FALSE, FALSE))
  expect_identical(upper(c(2, 1, 3, 4), .25), c(FALSE, FALSE, FALSE, TRUE))
  expect_identical(middle(c(2, 1, 3, 4), .5), c(TRUE, FALSE, TRUE, FALSE))
  expect_identical(tails(c(2, 1, 3, 4), .5), c(FALSE, TRUE, FALSE, TRUE))
})

test_that("it ignores NA values", {
  expect_identical(lower(c(2, 1, 3, 4, NA_real_), .25), c(FALSE, TRUE, FALSE, FALSE, rlang::na_lgl))
  expect_identical(upper(c(2, 1, 3, 4, NA_real_), .25), c(FALSE, FALSE, FALSE, TRUE, rlang::na_lgl))
  expect_identical(middle(c(2, 1, 3, 4, NA_real_), .5), c(TRUE, FALSE, TRUE, FALSE, rlang::na_lgl))
  expect_identical(tails(c(2, 1, 3, 4, NA_real_), .5), c(FALSE, TRUE, FALSE, TRUE, rlang::na_lgl))
})


# outer() tests -----------------------------------------------------------

test_that("outer(x, prop) is equivalent to tails(x, 1 - prop)", {
  x <- 1:1000
  expect_identical(
    suppressMessages(outer(x, .05)),
    tails(x, .95)
  )
  expect_identical(
    suppressMessages(outer(x, .10)),
    tails(x, .90)
  )
})

test_that("outer errors on prop <= 0 or prop >= 1", {
  expect_error(outer(1:10, 0))
  expect_error(outer(1:10, 1))
  expect_error(outer(1:10, -0.1))
  expect_error(outer(1:10, 1.5))
})

test_that("outer handles NA values the same as tails", {
  x <- c(2, 1, 3, 4, NA_real_)
  expect_identical(
    suppressMessages(outer(x, .5)),
    tails(x, .5)
  )
})

test_that("outer returns logical vector of correct length", {
  x <- 1:100
  result <- suppressMessages(outer(x, .05))
  expect_vector(result, logical(), 100)
})