test: add msw

Author: kantord

__tests__/msw-example.test.ts

@@ -0,0 +1,33 @@
+import { HttpResponse, http } from "msw";
+import { setupServer } from "msw/node";
+import { afterAll, afterEach, beforeAll, expect, test } from "vitest";
+
+const server = setupServer(
+  http.get("https://api.example.com/greet", () =>
+    HttpResponse.json({ message: "hello from msw" }),
+  ),
+);
+
+beforeAll(() => server.listen({ onUnhandledRequest: "error" }));
+afterEach(() => server.resetHandlers());
+afterAll(() => server.close());
+
+test("fetches mocked data from MSW handler", async () => {
+  const res = await fetch("https://api.example.com/greet");
+  expect(res.ok).toBe(true);
+  const json = (await res.json()) as { message: string };
+  expect(json).toEqual({ message: "hello from msw" });
+});
+
+test("can override handler per test", async () => {
+  server.use(
+    http.get("https://api.example.com/greet", () =>
+      HttpResponse.json({ message: "override" }),
+    ),
+  );
+
+  const res = await fetch("https://api.example.com/greet");
+  expect(res.ok).toBe(true);
+  const json = (await res.json()) as { message: string };
+  expect(json.message).toBe("override");
+});

package.json

@@ -22,6 +22,7 @@
     "better-auth": "1.4.0-beta.21",
     "class-variance-authority": "0.7.1",
     "clsx": "2.1.1",
+    "msw": "^2.12.2",
     "next": "16.0.3",
     "react": "19.2.0",
     "react-dom": "19.2.0",