test(unordered-list): add unit tests

tests/UnorderedList/UnorderedList.test.svelte

@@ -0,0 +1,30 @@
+<script lang="ts">
+  import { UnorderedList, ListItem } from "carbon-components-svelte";
+
+  export let nested = false;
+  export let expressive = false;
+  export let items: string[] = ["Item 1", "Item 2", "Item 3"];
+  export let nestedItems: string[] = [];
+</script>
+
+<UnorderedList
+  {nested}
+  {expressive}
+  on:click
+  on:mouseover
+  on:mouseenter
+  on:mouseleave
+>
+  {#each items as item}
+    <ListItem>
+      {item}
+      {#if nested && nestedItems.length > 0}
+        <UnorderedList nested>
+          {#each nestedItems as nestedItem}
+            <ListItem>{nestedItem}</ListItem>
+          {/each}
+        </UnorderedList>
+      {/if}
+    </ListItem>
+  {/each}
+</UnorderedList>