Migrating from clojure.test

A short video

I'm going to assume your test file looks like this:

     (ns my.test.ns
       (:use clojure.test))

     (deftest some-test ...)
     (deftest some-test ...)

Leave those old tests alone and just add facts to your test files:

     (ns my.test.ns
       (:use clojure.test)
       (:use midje.sweet))    ;; adding on...

     (deftest some-test ...)
     (deftest some-test ...)

     (fact (+ 1 1) => even?)  ;; adding on...

If you use Leiningen, install the leiningen plugin. You can then run lein midje to see output like this:

+++ The following shows how 'cake midje' checks facts in test files.
+++ The failure is intentional.

FAIL at (t_core.clj:13)
    Expected: "I am a test file fact"
      Actual: 3

+++ The following shows how 'cake midje' checks facts in source files.
+++ The failure is intentional.

FAIL at (core.clj:7)
    Expected: "I am a source-file fact."
      Actual: 3

+++ The following shows how 'cake midje' runs clojure.test deftests.
+++ The failure is intentional.
>>> Output from clojure.test tests:

FAIL in (a-clojure-test-test) (t_core.clj:8)
expected: (= 1 "I am a deftest expected result.")
  actual: (not (= 1 "I am a deftest expected result."))

>>> clojure.test summary:
Ran 1 tests containing 1 assertions.
1 failures, 0 errors.
>>> Midje summary:
FAILURE: 2 facts were not confirmed. 

Notice that both kinds of tests are run, and that summary results are reported correctly for both.

I don't recommend rewriting existing tests unless you are already changing them for some other reason.

Adapting setup and teardown logic

If existing clojure.test tests make use of setup/teardown logic (for instance, via use-fixtures), then this logic can also be migrated to midje using with-state-changes as described in Setup and teardown.

For example:

(def person (atom nil))
(defn create-state [] (reset! person "bill"))
(defn destroy-state [] (reset! person nil))

(defn my-test-fixture [f]
  (create-state)
  (f)
  (destroy-state))

(use-fixtures :each my-test-fixture)

(deftest person-is-named-bill
  (is (= "bill" @person)))

;; can be adapted to Midje using `with-state-changes`:
(with-state-changes [(before :facts (create-state))
                     (after :facts (destroy-state))]
  (fact @person => "bill"))