diff --git a/src/diffpy/pdfgui/tests/testaboutdialog.py b/src/diffpy/pdfgui/tests/testaboutdialog.py
index 1123d46d..44078276 100644
--- a/src/diffpy/pdfgui/tests/testaboutdialog.py
+++ b/src/diffpy/pdfgui/tests/testaboutdialog.py
@@ -43,11 +43,13 @@ def _clickbutton(self, button):
         self.dialog.ProcessEvent(e)
         return
 
+    def set_url(self, u):
+        setattr(self, "url", u)
+
     def test_LogoClicks(self):
         "Check handling of clicks on various logos"
         d = self.dialog
-        stealurl = lambda u: setattr(self, "url", u)
-        with overridewebbrowser(stealurl):
+        with overridewebbrowser(self.set_url):
             self._clickbutton(d.bitmap_button_nsf)
             self.assertTrue(self.url.endswith("www.nsf.gov"))
             self._clickbutton(d.bitmap_button_danse)