context("Area under the curve")

test_that("rectangle's method works", {
  expect_equal(
    area_rect(
      x = c(0, rep(0, 4), 0, sort(runif(3)), 1),
      y = c(0, sort(runif(4)), 1, rep(1, 3), 1)
    ),
    1
  )
  rand <- runif(7)
  expect_equal(area_rect(x = c(0, rand, 1), y = c(0, rand, 1)), 0.5)
  expect_equal(area_rect(x = c(0, 0, 0.5, 1), y = c(0, 0.5, 0.5, 1)), 5 / 8)
  expect_error(area_rect(x = rep(0, 4), y = rep(0, 6)))
})

values_letters <- runif(26)
names(values_letters) <- letters
true <- sample(letters, 10)
auc <- ebc_AUC(detection_values = values_letters, true = true, m = 26)

test_that("ebc_AUC() has the right behavior", {
  expect_is(auc, "numeric")
  expect_length(auc, 1)
  expect_error(ebc_AUC(
    detection_values = values_letters,
    true = true,
    m = 26,
    measures = c("FDR", "TPR")
  ))
})

test_that("AUC is the same with different directions", {
  expect_equal(
    ebc_AUC(
      detection_values = values_letters,
      true = true,
      m = 26,
      direction = "<="
    ),
    auc
  )
  expect_equal(
    ebc_AUC(
      detection_values = 1 - values_letters,
      true = true,
      m = 26,
      direction = ">"
    ),
    auc
  )
  expect_equal(
    ebc_AUC(
      detection_values = 1 - values_letters,
      true = true,
      m = 26,
      direction = ">="
    ),
    auc
  )
})

test_that("ebc_AUC_from_measures is correct", {
  df_measures <- ebc_tidy_by_threshold(values_letters, true, m = 26)
  expect_equal(ebc_AUC_from_measures(df_measures), auc)
  df_measures$FPR <- NULL
  expect_error(
    ebc_AUC_from_measures(df_measures),
    "df_measures must have a 'FPR' column."
  )
  df_measures$TPR <- NULL
  expect_error(
    ebc_AUC_from_measures(df_measures),
    "df_measures must have a 'TPR' column."
  )
})