Assert a re-used sequence number ends the hold it replaced

test/session-extras.test.ts

@@ -1526,14 +1526,15 @@ describe('held message bounds', () => {
 	test('is full at its count, and a re-used sequence number replaces rather than adding', () => {
 		const held = new HeldMessages({ log: silentLog, max: 2, maxOctets: 1_000_000, timeout: 10_000 });
 		const first = offer(held, 1);
+		const replaced = offer(held, 2);
 
-		offer(held, 2);
 		offer(held, 2);
 
 		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);
+		assert.equal(replaced.isHeld(), false);
 
 		held.clear();
 	});