; * test/src/fns-tests.el: Strengthen tests of `nreverse`.

1 files changed, 21 insertions, 18 deletions

diff --git a/test/src/fns-tests.el b/test/src/fns-tests.el
index 6f79d3277a8..2859123da80 100644
--- a/test/src/fns-tests.el
+++ b/test/src/fns-tests.el
@@ -114,22 +114,24 @@
   (should-error (nreverse 1))
   (should-error (nreverse (make-char-table 'foo)))
   (should (equal (nreverse (copy-sequence "xyzzy")) "yzzyx"))
-  (let ((A (vector)))
-    (nreverse A)
-    (should (equal A [])))
-  (let ((A (vector 0)))
-    (nreverse A)
-    (should (equal A [0])))
-  (let ((A (vector 1 2 3 4)))
-    (nreverse A)
-    (should (equal A [4 3 2 1])))
-  (let ((A (vector 1 2 3 4)))
-    (nreverse A)
-    (nreverse A)
-    (should (equal A [1 2 3 4])))
+  (let* ((A (vector))
+         (B (nreverse A)))
+    (should (equal A []))
+    (should (eq B A)))
+  (let* ((A (vector 0))
+         (B (nreverse A)))
+    (should (equal A [0]))
+    (should (eq B A)))
   (let* ((A (vector 1 2 3 4))
-         (B (nreverse (nreverse A))))
-    (should (equal A B))))
+         (B (nreverse A)))
+    (should (equal A [4 3 2 1]))
+    (should (eq B A)))
+  (let* ((A (vector 1 2 3 4))
+         (B (nreverse A))
+         (C (nreverse A)))
+    (should (equal A [1 2 3 4]))
+    (should (eq B A))
+    (should (eq C A))))
 
 (ert-deftest fns-tests-reverse-bool-vector ()
   (let ((A (make-bool-vector 10 nil)))
@@ -140,9 +142,10 @@
 (ert-deftest fns-tests-nreverse-bool-vector ()
   (let ((A (make-bool-vector 10 nil)))
     (dotimes (i 5) (aset A i t))
-    (nreverse A)
-    (should (equal [nil nil nil nil nil t t t t t] (vconcat A)))
-    (should (equal [t t t t t nil nil nil nil nil] (vconcat (nreverse A))))))
+    (let ((B (nreverse A)))
+      (should (eq B A))
+      (should (equal [nil nil nil nil nil t t t t t] (vconcat A)))
+      (should (equal [t t t t t nil nil nil nil nil] (vconcat (nreverse A)))))))
 
 (defconst fns-tests--string-lessp-cases
   `(("abc" < "abd")