test_that("efunc returns NA for NULL input", {
  error <- NULL
  expected <- NA
  result <- efunc(error)
  expect_identical(result, expected)
})


test_that("efunc returns NA for character string input", {
  error <- "Some error message"
  expected <- NA
  result <- efunc(error)
  expect_identical(result, expected)
})


test_that("rmvn generates multivariate normal data", {
  n <- 100
  sigma <- matrix(c(1, 0.5, 0.5, 1), nrow = 2)
  result <- rmvn(n, sigma)
  expect_equal(dim(result), c(n, 2))
})

test_that("nullToNA replaces null values with NA", {
  x <- c(1, NULL, 3, NULL, 5)
  result <- nullToNA(x)
  expect_equal(result, c(1, 3, 5))
})

test_that("try_na fuses nullToNA with efunc", {
  expect_equal(try_na(stop("An error occurred")), NA)
})

test_that("Null computes the null space of a matrix", {
  M <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 2)
  result <- Null(M)
  expect_equal(dim(result), c(2, 0))
})

test_that("resample on a non-empty vector returns correctly sized sample", {
  set.seed(123) # Setting seed for reproducibility
  result <- resample(1:10, size = 5)
  expect_equal(length(result), 5)
})

test_that("resample returns NA_integer_ for empty vector", {
  result <- resample(integer(0))
  expect_identical(result, NA_integer_)
})

test_that("resample with replacement behaves as expected", {
  set.seed(123)
  result <- resample(1:3, size = 10, replace = TRUE)
  expect_equal(length(result), 10)
  expect_true(all(result %in% 1:3))
})

test_that("resample with specific size returns correct length", {
  set.seed(123)
  result <- resample(1:10, size = 7)
  expect_equal(length(result), 7)
})

test_that("functions issue a deprecation warning", {
  #  skip_on_cran(message = "Skipping test that only checks for warning message")
  expect_warning(SimPed(), "deprecated")
  expect_warning(related_coef(), "deprecated")
  expect_warning(relatedness(obsR = .5), "deprecated")
})