test_that("exponential distribution works", {
  set.seed(1337L)
  expo <- dist_exponential()
  params <- list(rate = 2.0)
  x <- expo$sample(100L, with_params = params)

  expect_equal(fit_dist(expo, x)$params$rate, 1 / mean(x))
  expect_identical(expo$get_type(), "continuous")
  expect_density(expo, dexp, params, x)
  expect_probability(expo, pexp, params, x)
  expect_quantile(expo, qexp, params)
  expect_identical(expo$is_in_support(x), rep_len(TRUE, length(x)))
  expect_diff_density(expo, x, params)
  expect_diff_density(expo, x, list(rate = 4.0))
  expect_diff_probability(expo, x, params)
  expect_diff_probability(expo, x, list(rate = 4.0))
  expect_tf_logdensity(expo, params, x)
  expect_tf_logprobability(expo, params, x, x + 1.0)

  expect_tf_fit(expo, params, I_POSITIVE_REALS)
})