diff --git a/tests/nar.scm b/tests/nar.scm
index b8e50c7..37a357b 100644
--- a/tests/nar.scm
+++ b/tests/nar.scm
@@ -112,7 +112,8 @@
   (file-system-fold (const #t)
                     (lambda (name stat result)    ; leaf
                       (and result
-                           (file=? name (sibling name))))
+                           (pk 'file=? name (sibling name)
+                               (file=? name (sibling name)))))
                     (lambda (name stat result)    ; down
                       result)
                     (lambda (name stat result)    ; up

diff --git a/guix/tests.scm b/guix/tests.scm
index cd8eda2..efa1a6f 100644
--- a/guix/tests.scm
+++ b/guix/tests.scm
@@ -101,7 +101,8 @@
 
 (define (file=? a b)
   "Return true if files A and B have the same type and same content."
-  (and (eq? (stat:type (lstat a)) (stat:type (lstat b)))
+  (and (eq? (pk 'stat a  (stat:type (lstat a)))
+            (pk 'stat2 b (stat:type (lstat b))))
        (case (stat:type (lstat a))
          ((regular)
           (equal?