added unit tests for .clean_epidist_params and create_epidist_prob_di…

…st for exponential dist

tests/testthat/test-create_epidist_prob_dist.R

@@ -94,6 +94,22 @@ test_that("create_epidist_prob_dist works for poisson", {
   )
 })
 
+test_that("create_epidist_prob_dist works for exponential", {
+  res <- create_epidist_prob_dist(
+    prob_dist = "exp",
+    prob_dist_params = c(rate = 2),
+    discretise = FALSE,
+    truncation = NA
+  )
+
+  expect_s3_class(res, "distribution")
+  expect_identical(family(res), "exponential")
+  expect_identical(
+    distributional::parameters(res),
+    data.frame(rate = 2)
+  )
+})
+
 test_that("create_epidist_prob_dist works for discrete gamma", {
   res <- create_epidist_prob_dist(
     prob_dist = "gamma",

tests/testthat/test-epidist_utils.R

@@ -239,6 +239,36 @@ test_that(".clean_epidist_params fails when pois parameters are incorrect", {
   )
 })
 
+test_that(".clean_epidist_params works as expected for exp", {
+  params <- .clean_epidist_params(
+    prob_dist = "exp",
+    prob_dist_params = c(rate = 2)
+  )
+  expect_identical(params, c(rate = 2))
+
+  params <- .clean_epidist_params(
+    prob_dist = "exp",
+    prob_dist_params = c(lambda = 2)
+  )
+  expect_identical(params, c(rate = 2))
+
+  params <- .clean_epidist_params(
+    prob_dist = "exp",
+    prob_dist_params = c(mean = 0.5)
+  )
+  expect_identical(params, c(rate = 2))
+})
+
+test_that(".clean_epidist_params fails when exp parameters are incorrect", {
+  expect_error(
+    .clean_epidist_params(
+      prob_dist = "exp",
+      prob_dist_params = c(means = 1)
+    ),
+    regexp = "Invalid parameterisation for exp distribution"
+  )
+})
+
 test_that(".clean_epidist_params fails as expected", {
   expect_error(
     .clean_epidist_params(