diff --git a/tests/baz/1.0/IBaz.hal b/tests/baz/1.0/IBaz.hal
index 36d79cdc32..3e1e2b946b 100644
--- a/tests/baz/1.0/IBaz.hal
+++ b/tests/baz/1.0/IBaz.hal
@@ -57,4 +57,6 @@ interface IBaz extends IBase {
     returnABunchOfStrings() generates (string a, string b, string c);
 
     returnABitField() generates (bitfield<BitField> good);
+
+    size(uint32_t size) generates (uint32_t size);
 };