Overriding request handlers with MSW

Sometimes, either within your test or your implementation, you want to change what is being returned from a particular handler or you want to return an error. MSW allows you to do this with server.use.

const server = setupServer(  
	http.get('https://example.com/book/:bookId', () => {  
		return json({ title: 'Lord of the Rings' })  
	}),  
)  
  
afterEach(() => {  
	// Resets all runtime request handlers added via `server.use`  
	server.resetHandlers()  
})  
  
beforeAll(() => {  
	server.listen()  
})  
  
afterAll(() => {  
	server.close()  
})  
  
  
test('handles 500 errors from the API', () => {  
	server.use(  
		// Adds a runtime request handler for posting a new book review.  
		http.get('https://example.com/book/:bookId', () => {  
			return json({ error: 'Something went wrong' }, { status: 500 })  
		}),  
	)  
  
	// Performing a "GET /book/:bookId" request  
	// will get the mocked response from our runtime request handler.  
})  
  
test('asserts another scenario', () => {  
	// Since we call `server.resetHandlers()` after each test,  
	// this test suite will use the default GET /book/:bookId response.  
})