--- a/solfege/tests/test_lessonfile.py    2026-07-16 06:10:26.973612458 +0300
+++ b/solfege/tests/test_lessonfile.py  2026-07-16 06:12:58.458665911 +0300
@@ -1239,7 +1239,7 @@
             # This test only works with nrandom, because prandom will
             # return a possible different value every time.
             if rfunc == 'nrandom':
-                l = Gtk.Label(label=st)
+                l = Gtk.Label(label=str(st))
                 self.assertTrue(l.get_text() == str(st), "%s and gtk does not cooperate." % rfunc)