Refine =-body behavior

* Unwrap lists for :actual for `=` arity 2
* Use traditional clojure.test notation for `=` arity 3+

Fixes #735

Author: vemv

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Bugs fixed
 
+* [#735](https://github.com/clojure-emacs/cider-nrepl/issues/735): `middleware.test.extensions`: make `:actual` reporting clearer.
 * [#737](https://github.com/clojure-emacs/cider-nrepl/pull/737): Fix a regression in `middleware.out` that could result in duplicate output.
 
 ## 0.27.3 (2021-12-07)

src/cider/nrepl/middleware/test/extensions.clj

@@ -23,7 +23,13 @@
                            (map #(vector % (data/diff expected# %))))})
             (merge {:message ~msg
                     :expected expected#
-                    :actual more#})
+                    :actual
+                    (if (= 1 (count more#))
+                      ;; most times,` more` has a count of 1. For this case, we unwrap `more`,
+                      ;; which has been the traditional behavior of this feature:
+                      (first more#)
+                      ;; if `more` has 2+ arguments, our :actual will closely resemble clojure.test's own:
+                      (list ~''not (apply list ~(list 'quote '=) expected# more#)))})
             test/do-report)
        result#)
     `(throw (Exception. "= expects more than one argument"))))

test/clj/cider/nrepl/middleware/test/extensions_test.clj

@@ -1,7 +1,7 @@
 (ns cider.nrepl.middleware.test.extensions-test
   (:require
    [cider.nrepl.middleware.test.extensions :as extensions]
-   [clojure.test :refer :all]))
+   [clojure.test :refer [are deftest is testing]]))
 
 (deftest =-body-test
   (testing "Only evalulates expected form once"
@@ -20,4 +20,16 @@
              (- (swap! a inc) 6)
              (- (swap! a inc) 7)
              (- (swap! a inc) 8)
-             (- (swap! a inc) 9))))))
+             (- (swap! a inc) 9)))))
+  (testing ":actual is a scalar for (= x y) (i.e. arity 2)
+ and an informative list for (= x y z) (i.e. arity 3+)"
+    (are [subject args expected] (= expected
+                                    (let [proof (atom nil)]
+                                      (with-redefs [clojure.test/do-report
+                                                    (fn [m]
+                                                      (reset! proof m))]
+                                        (eval (extensions/=-body "_" subject args))
+                                        @proof)))
+      1 [1]   '{:expected 1, :actual 1, :message "_", :type :pass}
+      1 [2]   '{:expected 1, :actual 2, :message "_", :type :fail, :diffs ([2 [1 2 nil]])}
+      1 [2 3] '{:expected 1, :actual (not (= 1 2 3)), :message "_", :type :fail, :diffs ([2 [1 2 nil]] [3 [1 3 nil]])})))