test_that("Imputation", {
  set.seed(123)
  temp <- data.frame(
    c(NA, NA, 3:9, NA),
    c(NA, stats::rnorm(2), NA, stats::rnorm(6)),
    stats::rnorm(10),
    c(stats::rnorm(4), rep(NA, 3), stats::rnorm(3)),
    rep(NA, 10),
    c(stats::rnorm(1), rep(NA, 9)),
    c(stats::rnorm(9), NA),
    stats::rnorm(10),
    stats::rnorm(10),
    c(NA, NA, 3:9, NA)
  )
  temp_imp <- impute(X = temp, method = "zero")
  expect_equal(temp_imp$data[2, 1], 0)
  expect_equal(temp_imp$data[3, 5], 0)


  temp_imp <- impute(X = temp, method = "mean_obs")
  expect_equal(temp_imp$data[2, 1], 6)
  expect_equal(temp_imp$data[3, 5], as.numeric(NA))

  temp_imp <- impute(X = temp, method = "median_obs")
  expect_equal(temp_imp$data[2, 1], 6)
  expect_equal(temp_imp$data[3, 5], as.numeric(NA))


  temp_imp <- impute(X = temp, method = "mean_data")
  expect_equal(round(temp_imp$data[2, 1], 4), -0.1958)
  expect_equal(round(temp_imp$data[3, 5], 4), 0.5324)

  temp_imp <- impute(X = temp, method = "median_data")
  expect_equal(round(temp_imp$data[2, 1], 4), -0.4243)
  expect_equal(round(temp_imp$data[3, 5], 4), -0.1460)


  temp_imp <- impute(temp, method = "linear", obs_share_data = TRUE)
  expect_equal(temp_imp$data[2, 1], 2)
  expect_equal(round(temp_imp$data[4, 2], 4), 0.6643)
  expect_equal(round(temp_imp$data[3, 5], 4), -0.9146)

  expect_error(impute(temp, method = "functional"))
  temp_imp <- impute(temp[, 3:4], method = "functional")
  expect_equal(round(temp_imp$data[5, 2], 4), -0.9702)
})