library(testthat)
library(AutoEDA)
library(ggplot2)

#==========================================================
# cluster_elbow()
#==========================================================

test_that("cluster_elbow returns ggplot", {

  skip_if_not_installed("factoextra")

  p <- cluster_elbow(iris)

  expect_s3_class(
    p,
    "ggplot"
  )

})

test_that("cluster_elbow works with numeric-only data", {

  skip_if_not_installed("factoextra")

  expect_no_error(

    cluster_elbow(
      iris[, 1:4]
    )

  )

})

test_that("cluster_elbow works with tibble", {

  skip_if_not_installed("factoextra")
  skip_if_not_installed("tibble")

  dat <- tibble::as_tibble(iris)

  expect_no_error(

    cluster_elbow(dat)

  )

})

#==========================================================
# Invalid input
#==========================================================

test_that("cluster_elbow rejects non-data.frame", {

  expect_error(

    cluster_elbow(
      1:10
    )

  )

})

test_that("cluster_elbow rejects NULL", {

  expect_error(

    cluster_elbow(
      NULL
    )

  )

})

test_that("cluster_elbow rejects character vector", {

  expect_error(

    cluster_elbow(
      letters
    )

  )

})

test_that("cluster_elbow rejects empty data.frame", {

  expect_error(

    cluster_elbow(
      data.frame()
    )

  )

})

test_that("cluster_elbow rejects one numeric variable", {

  expect_error(

    cluster_elbow(
      data.frame(
        x = 1:10
      )
    )

  )

})

test_that("cluster_elbow rejects non-numeric data", {

  expect_error(

    cluster_elbow(

      data.frame(
        A = letters[1:10],
        B = LETTERS[1:10]
      )

    )

  )

})

test_that("cluster_elbow rejects mixed numeric and character data", {

  expect_error(

    cluster_elbow(

      data.frame(
        x = 1:10,
        y = letters[1:10]
      )

    )

  )

})

test_that("cluster_elbow rejects missing values", {

  dat <- iris
  dat$Sepal.Length[1:10] <- NA

  expect_error(

    cluster_elbow(dat),

    "Missing values"

  )

})