AI scaffolded NodeJS version of the App.

app-new/frontend/test/app.test.tsx

@@ -0,0 +1,48 @@
+import { render, screen } from "@testing-library/react";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { ThemeProvider, createTheme } from "@mui/material";
+import { beforeEach, afterEach, describe, expect, it, vi } from "vitest";
+import App from "../src/App";
+
+const originalFetch = globalThis.fetch;
+
+const createResponse = (payload: unknown) =>
+  new Response(JSON.stringify(payload), {
+    status: 200,
+    headers: { "Content-Type": "application/json" }
+  });
+
+describe("App", () => {
+  beforeEach(() => {
+    globalThis.fetch = vi.fn((url: string) => {
+      if (url === "/api/locations") {
+        return Promise.resolve(createResponse([{ name: "westeurope", displayName: "West Europe" }]));
+      }
+
+      if (url === "/api/templates") {
+        return Promise.resolve(createResponse([{ label: "Azure CLI", language: "shell", file: "shell.tpl" }]));
+      }
+
+      return Promise.resolve(createResponse([]));
+    }) as typeof fetch;
+  });
+
+  afterEach(() => {
+    globalThis.fetch = originalFetch;
+  });
+
+  it("renders application heading", async () => {
+    const client = new QueryClient();
+    const theme = createTheme();
+
+    render(
+      <QueryClientProvider client={client}>
+        <ThemeProvider theme={theme}>
+          <App />
+        </ThemeProvider>
+      </QueryClientProvider>
+    );
+
+    expect(await screen.findByText("Azure Image Chooser")).toBeInTheDocument();
+  });
+});