tests/testthat/test-dist-cauchy.R

In distributional: Vectorised Probability Distributions

test_that("Cauchy distribution", {
  dist <- dist_cauchy(-2, 1)

  expect_equal(format(dist), "Cauchy(-2, 1)")

  # quantiles
  expect_equal(quantile(dist, 0.1), stats::qcauchy(0.1, -2, 1))
  expect_equal(quantile(dist, 0.5), stats::qcauchy(0.5, -2, 1))

  # pdf
  expect_equal(density(dist, 0), stats::dcauchy(0, -2, 1))
  expect_equal(density(dist, 3), stats::dcauchy(3, -2, 1))

  # cdf
  expect_equal(cdf(dist, 0), stats::pcauchy(0, -2, 1))
  expect_equal(cdf(dist, 3), stats::pcauchy(3, -2, 1))

  # F(Finv(a)) ~= a
  expect_equal(cdf(dist, quantile(dist, 0.4246)), 0.4246, tolerance = 1e-3)

  # stats
  expect_equal(mean(dist), NA_real_)
  expect_equal(variance(dist), NA_real_)
})