add snapshot test

src/AppBar.test.tsx

@@ -0,0 +1,25 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { render } from "@testing-library/react";
+import { describe, expect, it } from "vitest";
+import { TooltipProvider } from "@vector-im/compound-web";
+
+import { AppBar } from "./AppBar";
+
+describe("AppBar", () => {
+  it("renders", () => {
+    const { container } = render(
+      <TooltipProvider>
+        <AppBar>
+          <p>This is the content.</p>
+        </AppBar>
+      </TooltipProvider>,
+    );
+    expect(container).toMatchSnapshot();
+  });
+});

src/__snapshots__/AppBar.test.tsx.snap

@@ -0,0 +1,50 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`AppBar > renders 1`] = `
+<div>
+  <div
+    class="bar"
+    style="display: block;"
+  >
+    <header
+      class="header"
+    >
+      <div
+        class="nav leftNav"
+      >
+        <button
+          aria-labelledby="«r0»"
+          class="_icon-button_1pz9o_8"
+          data-kind="primary"
+          role="button"
+          style="--cpd-icon-button-size: 32px;"
+          tabindex="0"
+        >
+          <div
+            class="_indicator-icon_zr2a0_17"
+            style="--cpd-icon-button-size: 100%;"
+          >
+            <svg
+              fill="currentColor"
+              height="1em"
+              viewBox="0 0 24 24"
+              width="1em"
+              xmlns="http://www.w3.org/2000/svg"
+            >
+              <path
+                d="M12.207 5.293a1 1 0 0 1 0 1.414L7.914 11H18.5a1 1 0 1 1 0 2H7.914l4.293 4.293a1 1 0 0 1-1.414 1.414l-6-6a1 1 0 0 1 0-1.414l6-6a1 1 0 0 1 1.414 0"
+              />
+            </svg>
+          </div>
+        </button>
+      </div>
+      <div
+        class="nav rightNav"
+      />
+    </header>
+  </div>
+  <p>
+    This is the content.
+  </p>
+</div>
+`;