Make ert explainers work on function aliases

* lisp/emacs-lisp/ert.el: New function.
(ert--expand-should-1): Use it (bug#53178).

2 files changed, 14 insertions, 6 deletions

diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index e31ebf5f7bb..9c6b0e15bbe 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -335,15 +335,20 @@ It should only be stopped when ran from inside `ert--run-test-internal'."
                                  (unless (eql ,value ',default-value)
                                    (list :value ,value))
                                  (unless (eql ,value ',default-value)
-                                   (let ((-explainer-
-                                          (and (symbolp ',fn-name)
-                                               (get ',fn-name 'ert-explainer))))
-                                     (when -explainer-
-                                       (list :explanation
-                                             (apply -explainer- ,args))))))
+                                   (when-let ((-explainer-
+                                               (ert--get-explainer ',fn-name)))
+                                     (list :explanation
+                                           (apply -explainer- ,args)))))
                          value)
                ,value))))))))
 
+(defun ert--get-explainer (fn-name)
+  (when (symbolp fn-name)
+    (cl-loop for fn in (cons fn-name (function-alias-p fn-name))
+             for explainer = (get fn 'ert-explainer)
+             when explainer
+             return explainer)))
+
 (defun ert--expand-should (whole form inner-expander)
   "Helper function for the `should' macro and its variants.
 
diff --git a/test/lisp/emacs-lisp/ert-tests.el b/test/lisp/emacs-lisp/ert-tests.el
index ac130644743..270cca1c2e7 100644
--- a/test/lisp/emacs-lisp/ert-tests.el
+++ b/test/lisp/emacs-lisp/ert-tests.el
@@ -881,6 +881,9 @@ This macro is used to test if macroexpansion in `should' works."
   "Check that `lexical-binding' in `ert-deftest' has the file value."
   (should (equal lexical-binding t)))
 
+(ert-deftest ert-test-get-explainer ()
+  (should (eq (ert--get-explainer 'string-equal) 'ert--explain-string-equal))
+  (should (eq (ert--get-explainer 'string=) 'ert--explain-string-equal)))
 
 (provide 'ert-tests)