diff --git a/tests/test-extension.t b/tests/test-extension.t
--- a/tests/test-extension.t
+++ b/tests/test-extension.t
@@ -1681,6 +1681,10 @@
   > baduisetup = $TESTTMP/baduisetup.py
   > EOF
 
+The tests below requires demandimport to be enabled.
+
+  $ HGDEMANDIMPORT=enable
+
 Even though the extension fails during uisetup, hg is still basically usable:
   $ hg version
   \*\*\* failed to set up extension baduisetup: No module named (mercurial\.)?bdiff (re)