[Test] Add test for class directive with spread attributes

test/runtime/samples/class-with-dynamic-attribute-and-spread/_config.js

@@ -0,0 +1,21 @@
+export default {
+	props: {
+		myClass: 'one two',
+		attributes: {
+			role: 'button'
+		}
+	},
+
+	html: `<div class="one two three" role="button"></div>`,
+
+	test({ assert, component, target, window }) {
+		component.myClass = 'one';
+		component.attributes = {
+			'aria-label': 'Test'
+		};
+
+		assert.htmlEqual(target.innerHTML, `
+			<div class="one three" aria-label="Test"></div>
+		`);
+	}
+};

test/runtime/samples/class-with-dynamic-attribute-and-spread/main.svelte

@@ -0,0 +1,6 @@
+<script>
+	export let myClass;
+	export let attributes = {};
+</script>
+
+<div class={myClass} class:three={true} {...attributes}></div>