How can I check for thrown exceptions in Clojure?

When testing code, I also like the failure conditions.

I'm new to Clojure, but how can I test a thrown exception?

I would like to test the following example code:

(ns com.stackoverflow.clojure.tests)

(defn casetest [x]
  (case x
    "a" "An a."
    "b" "A b."
    (-> (clojure.core/format "Expression '%s' not defined." x)
        (IllegalArgumentException.)
        (throw))))

      

with the following test methods:

(ns com.stackoverflow.clojure.tests-test
  (:require [clojure.test :refer :all]
            [com.stackoverflow.clojure.tests :refer :all]))

(deftest casetest-tests
  (is (= "An a." (casetest "a")))
  (is (= "A b."  (casetest "b")))
  (throws-excpeption IllegalArgumentException. (casetest "c")) ; conceptual code
  )

(run-tests)

      

My .clj project looks like this:

(defproject com.stackoverflow.clojure/tests "0.1.0-SNAPSHOT"
  :description "Tests of Clojure test-framework."
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.6.0"]])

      

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1 answer


You can test the thrown exception with (is (thrown? ExpectedExceptionClass body))



See http://clojure.github.io/clojure/clojure.test-api.html

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