test(combo-box): add unit tests

tests/ComboBox/ComboBox.test.svelte

@@ -0,0 +1,49 @@
+<script lang="ts">
+  import { ComboBox } from "carbon-components-svelte";
+  import type { ComboBoxItem } from "carbon-components-svelte/ComboBox/ComboBox.svelte";
+
+  export let items: ComboBoxItem[] = [
+    { id: "0", text: "Slack" },
+    { id: "1", text: "Email" },
+    { id: "2", text: "Fax" },
+  ];
+  export let selectedId: string | undefined = undefined;
+  export let value = "";
+  export let disabled = false;
+  export let invalid = false;
+  export let warn = false;
+  export let light = false;
+  export let open = false;
+  export let titleText = "Contact";
+  export let placeholder = "Select contact method";
+  export let invalidText = "";
+  export let warnText = "";
+  export let helperText = "";
+  export let size: "sm" | "xl" | undefined = undefined;
+  export let shouldFilterItem = (item: ComboBoxItem, value: string) =>
+    item.text.toLowerCase().includes(value.toLowerCase());
+</script>
+
+<ComboBox
+  {disabled}
+  {helperText}
+  {invalid}
+  {invalidText}
+  {items}
+  {light}
+  {open}
+  {placeholder}
+  {selectedId}
+  {size}
+  {titleText}
+  {value}
+  {warn}
+  {warnText}
+  {shouldFilterItem}
+  on:select={(e) => {
+    console.log("select", e.detail);
+  }}
+  on:clear={(e) => {
+    console.log("clear", e.type);
+  }}
+/>