diff --git a/test/session-extras.test.ts b/test/session-extras.test.ts
index c8b3dc2..fb11cad 100644
--- a/test/session-extras.test.ts
+++ b/test/session-extras.test.ts
@@ -1508,6 +1508,7 @@ describe('held message bounds', () => {
 		held.hold(message(2), 1);
 
 		assert.equal(held.size, 2);
+		assert.equal(held.octetsHeld, 2 * 1026, 'the replaced message leaves its octets with it');
 		assert.equal(held.full(), true);
 		assert.equal(first.isHeld(), true);