test_that("Changes found", {
  set.seed(123)
  res <- .change_mean(electricity, M = 250)
  expect_equal(res$pvalue, 0)
  expect_equal(res$location, 124)
})

test_that("Simple changes found", {
  set.seed(123)
  data <- data.frame(
    rep(1, 10), rep(1, 10), rep(1, 10),
    rep(10, 10), rep(10, 10), rep(10, 10)
  )
  res <- .change_mean(data, M = 250)
  expect_equal(res$location, 3)
})

test_that("Data type error caught", {
  expect_error(
    .change_mean(1:10, M = 250),
    "Data type"
  )
})

test_that("Statistic error caught", {
  expect_error(
    .change_mean(electricity, statistic = "Qn", M = 250),
    "statistic"
  )
})