test_that("can collapse multiple values", {
  f1 <- factor(letters[1:3])
  f2 <- fct_collapse(f1, x = c("a", "b"), y = "c")

  expect_equal(f2, factor(c("x", "x", "y")))
})

test_that("empty dots yields unchanged factor", {
  f1 <- factor(letters[1:3])
  f2 <- fct_collapse(f1)

  expect_identical(f1, f2)
})

test_that("can collapse missing levels", {
  f1 <- factor(c("x", NA), exclude = NULL)
  f2 <- fct_collapse(f1, y = NA_character_)

  expect_equal(f2, factor(c("x", "y")))
})

test_that("can collapse un-named levels", {
  f <- factor(letters[1:3])

  expect_equal(
    fct_collapse(f, xy = c("a", "b"), other_level = "Other"),
    fct(c("xy", "xy", "Other"), levels = c("xy", "Other"))
  )

  expect_equal(
    fct_collapse(f, xy = c("a", "b"), other_level = NA),
    fct(c("xy", "xy", NA), levels = c("xy", NA))
  )
})

test_that("collapses levels correctly when group_other is TRUE but no other variables to group", {
  f1 <- factor(letters[1:4])
  f2 <- fct_collapse(f1, x1 = c("a", "b", "d"), x2 = "c", other_level = "Other")

  expect_equal(f2, factor(c("x1", "x1", "x2", "x1"), levels = c("x1", "x2")))
})

test_that("collapses levels correctly when group_other is TRUE and some Other variables to group", {
  f1 <- factor(letters[1:4])
  f2 <- fct_collapse(f1, x1 = c("a", "d"), x2 = "c", other_level = "Other")

  expect_equal(
    f2,
    factor(c("x1", "Other", "x2", "x1"), levels = c("x1", "x2", "Other"))
  )
})

test_that("does not automatically collapse unnamed levels to Other", {
  f1 <- factor(letters[1:3])
  f2 <- fct_collapse(f1, xy = c("a", "b"))

  expect_equal(f2, factor(c("xy", "xy", "c"), levels = c("xy", "c")))
})

test_that("group_other is deprecated", {
  f1 <- factor(letters[1:4])
  expect_snapshot(
    f2 <- fct_collapse(f1, x1 = c("a", "d"), x2 = "c", group_other = TRUE)
  )

  expect_equal(levels(f2), c("x1", "x2", "Other"))
})


test_that("valdiates inputs", {
  expect_snapshot(error = TRUE, {
    fct_collapse(1)
    fct_collapse("x", other_level = 1)
  })
})