test_that("NuPrime correctly calculated", {
  values <- seq(0, 1, 0.001)
  mdnu <- function(u, cp) {
    -2 * (qnorm(cp) - qnorm(u)) / dnorm(qnorm(u))
  }
  expect_equal(mdnu(values, 0.8), getNuPrime(values, conditionalPower = 0.8), tolerance = 1e-8)
  expect_equal(mdnu(values, 0.9), getNuPrime(values, conditionalPower = 0.9), tolerance = 1e-8)
})