feat(ai-character): Mock Preview 모드 구현

src/shared/mocks/browser.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, test, vi } from "vitest";
+
+const { setupWorkerMock, workerStart } = vi.hoisted(() => {
+  const workerStart = vi.fn();
+  const setupWorkerMock = vi.fn(() => ({ start: workerStart }));
+
+  return { setupWorkerMock, workerStart };
+});
+
+vi.mock("msw/browser", () => ({
+  setupWorker: setupWorkerMock,
+}));
+
+import { startMockWorker } from "./browser";
+
+describe("startMockWorker", () => {
+  test("starts browser MSW with an error policy for unhandled requests", async () => {
+    // Given
+    vi.stubEnv("VITE_API_BASE_URL", "https://api.example.com");
+    const startOptions = { onUnhandledRequest: "error" };
+
+    // When
+    await startMockWorker();
+
+    // Then
+    expect(setupWorkerMock).toHaveBeenCalledWith(expect.anything(), expect.anything(), expect.anything());
+    expect(workerStart).toHaveBeenCalledWith(startOptions);
+  });
+});