chore: add test for ExpiredIteratorException

though it will only work on a machine with oldShardState.json
which I'm currently loath to share as is.
fix #9

Author: kessler

.gitignore

@@ -30,5 +30,6 @@ node_modules/*
 
 index2.js
 test2.js
-shardState.json*
+shardState.json
+oldShardState.json
 playground

test.js

@@ -40,6 +40,14 @@ test('reports the correct stream of changes', async t => {
 	])
 })
 
+// this test will only work if you have a proper shardState set a side
+test.skip('ExpiredIteratorException', async t => {
+	const shardState = require('./oldShardState.json')
+	const { ddbStream } = t.context
+	ddbStream.setShardState(shardState)
+	await t.notThrowsAsync(ddbStream.fetchStreamState())
+})
+
 test.beforeEach(async t => {
 
 	t.context = {