diff --git a/tests/virsh-optparse b/tests/virsh-optparse
index cb0f3d4f3d1ccdde8904dbb8eb353ed47d29cd55..1aef8d8d95aec4cb841cdc6a4e4c80d8ea4feef0 100755
--- a/tests/virsh-optparse
+++ b/tests/virsh-optparse
@@ -212,6 +212,7 @@ compare exp-err err || fail=1
 # Numeric value with invalid suffix
 cat <<\EOF > exp-err || framework_failure
 error: Scaled numeric value '42WB' for <size> option is malformed or out of range
+error: invalid argument: unknown suffix 'WB'
 EOF
 virsh -q -c $test_url setmaxmem test 42WB >out 2>err && fail=1
 test -s out && fail=1