test_that("complete with no variables returns data as is", {
  expect_equal(complete(mtcars), mtcars)
})

test_that("basic invocation works", {
  df <- tibble(x = 1:2, y = 1:2, z = 3:4)
  out <- complete(df, x, y)
  expect_equal(nrow(out), 4)
  expect_equal(out$z, c(3, NA, NA, 4))
})

test_that("will complete within each group (#396)", {
  levels <- c("a", "b", "c")

  df <- tibble(
    g = c("a", "b", "a"),
    a = c(1L, 1L, 2L),
    b = factor(c("a", "a", "b"), levels = levels),
    c = c(4, 5, 6)
  )
  gdf <- dplyr::group_by(df, g)

  out <- complete(gdf, a, b)

  # Still grouped
  expect_identical(dplyr::group_vars(out), "g")

  out <- nest(out, data = -g)

  expect_identical(
    out$data[[1]],
    tibble(
      a = vec_rep_each(c(1L, 2L), times = 3),
      b = factor(vec_rep(c("a", "b", "c"), times = 2)),
      c = c(4, NA, NA, NA, 6, NA)
    )
  )

  expect_identical(
    out$data[[2]],
    tibble(
      a = 1L,
      b = factor(c("a", "b", "c")),
      c = c(5, NA, NA)
    )
  )
})

test_that("complete does not allow expansion on grouping variable (#1299)", {
  df <- tibble(
    g = "x",
    a = 1L
  )
  gdf <- dplyr::group_by(df, g)

  # This is a dplyr error that we don't own
  expect_error(complete(gdf, g))
})

test_that("can use `.drop = FALSE` with complete (#1299)", {
  levels <- c("a", "b", "c")

  df <- tibble(
    g = factor(c("a", "b", "a"), levels = levels),
    a = c(1L, 1L, 2L),
    b = factor(c("a", "a", "b"), levels = levels)
  )
  gdf <- dplyr::group_by(df, g, .drop = FALSE)

  # No data in group "c" for `a`, so we don't get that in the result
  expect_identical(
    complete(gdf, a),
    vec_sort(gdf)
  )

  expect <- crossing(g = factor(levels = levels), b = factor(levels = levels))
  expect <- dplyr::group_by(expect, g, .drop = FALSE)
  expect <- dplyr::full_join(expect, df, c("g", "b"))

  # Levels of empty vector in `b` are expanded for group "c"
  expect_identical(complete(gdf, b), expect)
})

test_that("complete moves the grouping and completing variables to the front", {
  df <- tibble(
    a = 1L,
    g = "x",
    b = 2L
  )
  gdf <- dplyr::group_by(df, g)

  expect_named(complete(gdf, b), c("g", "b", "a"))
})

test_that("expands empty factors", {
  f <- factor(levels = c("a", "b", "c"))
  df <- tibble(one = f, two = f)

  expect_equal(nrow(complete(df, one, two)), 9)
  expect_equal(ncol(complete(df, one, two)), 2)
})

test_that("empty expansion returns original", {
  df <- tibble(x = character())
  rs <- complete(df, y = NULL)
  expect_equal(rs, df)

  df <- tibble(x = 1:4)
  rs <- complete(df, y = NULL)
  expect_equal(rs, df)
})

test_that("not drop unspecified levels in complete", {
  df <- tibble(x = 1:3, y = 1:3, z = c("a", "b", "c"))
  df2 <- df %>% complete(z = c("a", "b"))
  expect <- df[c("z", "x", "y")]
  expect_equal(df2, expect)
})

test_that("complete() with empty nesting() / crossing() calls 'ignores' them (#1258)", {
  df <- tibble(x = factor(c("a", "c"), letters[1:3]))

  expect_identical(complete(df, x), complete(df, x, nesting()))
  expect_identical(complete(df, x), complete(df, x, crossing()))

  expect_identical(complete(df, x), complete(df, x, nesting(NULL)))
  expect_identical(complete(df, x), complete(df, x, crossing(NULL)))
})

test_that("complete() fills missing values even when there are no `...` (#1272)", {
  df <- tibble(a = c(1, NA, 3))

  expect_identical(
    complete(df, fill = list(a = 0)),
    tibble(a = c(1, 0, 3))
  )
})

test_that("both implicit and explicit missing values are filled by default", {
  df <- tibble(
    x = factor(1:2, levels = 1:3),
    a = c(1, NA)
  )

  expect_identical(
    complete(df, x, fill = list(a = 0)),
    tibble(x = factor(1:3), a = c(1, 0, 0))
  )
})

test_that("can limit the fill to only implicit missing values with `explicit` (#1270)", {
  df <- tibble(
    x = factor(1:2, levels = 1:3),
    a = c(1, NA)
  )

  expect_identical(
    complete(df, x, fill = list(a = 0), explicit = FALSE),
    tibble(x = factor(1:3), a = c(1, NA, 0))
  )
})

test_that("can't fill a grouping column", {
  df <- tibble(
    g = c(1, NA),
    x = factor(1:2, levels = 1:3)
  )
  gdf <- dplyr::group_by(df, g)

  # Silently ignore it
  out <- complete(gdf, x, fill = list(g = 0))

  expect_identical(out$g, c(1, 1, 1, NA, NA, NA))
})

test_that("if the completing variables have missings, `fill` will fill them after expansion", {
  # This behavior is admittedly a little weird, but should not be common
  # because you rarely specify a completing variable in `fill`

  df <- tibble(
    x = c(1, NA),
    y = c(NA, 1)
  )

  # Expanded combinations that involved missings get filled
  expect_identical(
    complete(df, x, y, fill = list(x = 0, y = 0)),
    tibble(x = c(1, 1, 0, 0), y = c(1, 0, 1, 0))
  )

  # Can limit the fill to only the "new" combinations that weren't in the
  # original data. Here, the `x = NA, y = NA` combination that gets created.
  expect_identical(
    complete(df, x, y, fill = list(x = 0, y = 0), explicit = FALSE),
    tibble(x = c(1, 1, NA, 0), y = c(1, NA, 1, 0))
  )
})


test_that("validates its inputs", {
  expect_snapshot(error = TRUE, {
    complete(mtcars, explicit = 1)
  })
})