portainer/app/setup-tests/setup-msw.ts

// test/setup-env.js
// add this to your setupFilesAfterEnv config in jest so it's imported for every test file
import { server } from './server';

beforeAll(() => server.listen());
// if you need to add a handler after calling setupServer for some specific test
// this will remove that handler for the rest of them
// (which is important for test isolation):
afterEach(() => server.resetHandlers());
afterAll(() => server.close());