Add tests for model service navigation (#4350)

static/js/brand-store/components/Model/ModelNav.test.tsx

@@ -0,0 +1,28 @@
+import React from "react";
+import { BrowserRouter } from "react-router-dom";
+import { render, screen } from "@testing-library/react";
+import "@testing-library/jest-dom";
+
+import ModelNav from "./ModelNav";
+
+const renderComponent = () => {
+  return render(
+    <BrowserRouter>
+      <ModelNav sectionName="policies" />
+    </BrowserRouter>
+  );
+};
+
+describe("ModelNav", () => {
+  it("highlights the correct navigation item", () => {
+    renderComponent();
+    const currentLink = screen.getByRole("tab", { name: "Policies" });
+    expect(currentLink.getAttribute("aria-selected")).toBe("true");
+  });
+
+  it("doesn't highlight other navigation links", () => {
+    renderComponent();
+    const currentLink = screen.getByRole("tab", { name: "Overview" });
+    expect(currentLink.getAttribute("aria-selected")).toBe("false");
+  });
+});