diff --git a/tests/testthat/test-monster_creator.R b/tests/testthat/test-monster_creator.R
new file mode 100644
index 0000000..6cb5e25
--- /dev/null
+++ b/tests/testthat/test-monster_creator.R
@@ -0,0 +1,26 @@
+# Run all tests in this script:
+## testthat::test_file(file.path("tests", "testthat", "test-monster_creator.R"))
+
+# Error testing
+test_that("Errors work as desired", {
+  expect_error(monster_creator(party_level = NULL, party_size = NULL))
+  expect_error(monster_creator(party_level = 6, party_size = NULL))
+  expect_error(monster_creator(party_level = NULL, party_size = 4))
+  expect_error(monster_creator(party_level = "six", party_size = 4))
+  expect_error(monster_creator(party_level = 6, party_size = "four"))
+})
+
+# # Warning testing
+# test_that("Warnings work as desired", {
+#   # No warnings in this function
+# })
+
+# # Message testing
+# test_that("Messages work as desired", {
+#   # No messages in this function
+# })
+
+# Output testing
+test_that("Outputs are as expected", {
+  expect_equal(class(monster_creator(party_level = 4, party_size = 4)), "data.frame")
+})