diff --git a/gnu/packages/python-xyz.scm b/gnu/packages/python-xyz.scm
index e04b4f973f..fff2f06835 100644
--- a/gnu/packages/python-xyz.scm
+++ b/gnu/packages/python-xyz.scm
@@ -65,7 +65,7 @@
 ;;; Copyright © 2019 Jacob MacDonald <jaccarmac@gmail.com>
 ;;; Copyright © 2019, 2020, 2021 Giacomo Leidi <goodoldpaul@autistici.org>
 ;;; Copyright © 2019 Wiktor Żelazny <wzelazny@vurv.cz>
-;;; Copyright © 2019, 2020, 2021 Tanguy Le Carrour <tanguy@bioneland.org>
+;;; Copyright © 2019, 2020, 2021, 2022 Tanguy Le Carrour <tanguy@bioneland.org>
 ;;; Copyright © 2019, 2021 Mădălin Ionel Patrașcu <madalinionel.patrascu@mdc-berlin.de>
 ;;; Copyright © 2020 Riku Viitanen <riku.viitanen@protonmail.com>
 ;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
@@ -8893,6 +8893,7 @@ (define-public python-urwidtrees
     (arguments
      '(#:tests? #f)) ; no tests
     (propagated-inputs (list python-urwid))
+    (native-inputs (list python-mock))
     (home-page "https://github.com/pazz/urwidtrees")
     (synopsis "Tree widgets for urwid")
     (description "Urwidtrees is a Widget Container API for the @code{urwid}