diff --git a/types/src/tests/mod.rs b/types/src/tests/mod.rs
index 42f5966e6..f010f070f 100644
--- a/types/src/tests/mod.rs
+++ b/types/src/tests/mod.rs
@@ -4,6 +4,7 @@ mod parse;
 mod serialize;
 mod variant;
 mod hello;
+mod supported_message;
 
 use std::fmt::Debug;
 use std::cmp::PartialEq;
diff --git a/types/src/tests/supported_message.rs b/types/src/tests/supported_message.rs
new file mode 100644
index 000000000..dd73f0d8d
--- /dev/null
+++ b/types/src/tests/supported_message.rs
@@ -0,0 +1,10 @@
+use crate::supported_message::SupportedMessage;
+
+#[test]
+fn size() {
+    // Test that the SupportedMessage size isn't huge
+    use std::mem;
+    let size = mem::size_of::<SupportedMessage>();
+    println!("SupportedMessage size = {}", size);
+    assert!(size <= 16);
+}