diff --git a/tests/cmdMZ.test b/tests/cmdMZ.test
index 9af30bd583f..b985e55b701 100644
--- a/tests/cmdMZ.test
+++ b/tests/cmdMZ.test
@@ -55,7 +55,7 @@ test cmdMZ-1.4 {Tcl_PwdObjCmd: failure} -setup {
     file delete -force $foodir
     file mkdir $foodir
     cd $foodir
-} -constraints {Unix nonPortable} -body {
+} -constraints {unix nonPortable} -body {
     # This test fails on various Unix platforms (eg Linux) where permissions
     # caching causes this to fail. The caching is strictly incorrect, but we
     # have no control over that.