add unit test

test/runtime/samples/select-props/_config.js

@@ -0,0 +1,15 @@
+export default {
+	test ( assert, component, target, window ) {
+		const selects = document.querySelectorAll( 'select' );
+
+		const event1 = new window.Event( 'change' );
+		selects[0].value = 'b';
+		selects[0].dispatchEvent(event1);
+
+		const event2 = new window.Event( 'change' );
+		selects[1].value = 'b';
+		selects[1].dispatchEvent(event2);
+
+		assert.deepEqual( component.get( 'log' ), [ 1, 2 ] );
+	}
+};

test/runtime/samples/select-props/main.html

@@ -0,0 +1,19 @@
+{{#each foo as bar}}
+	<select on:change='handler(bar)'>
+		<option>a</option>
+		<option>b</option>
+	</select>
+{{/each}}
+
+<script>
+	export default {
+		data: () => ({ foo: [ 1, 2 ], log: [] }),
+		methods: {
+			handler ( bar ) {
+				let { log } = this.get();
+				log.push( bar );
+				this.set( { log } );
+			}
+		}
+	}
+</script>