test(fetch): add "bodyUsed" compliance

test/modules/fetch/compliance/fetch-request-body-used.test.ts

@@ -0,0 +1,130 @@
+import { it, expect, beforeAll, afterEach, afterAll } from 'vitest'
+import * as express from 'express'
+import { HttpServer } from '@open-draft/test-server/http'
+import { FetchInterceptor } from '../../../../src/interceptors/fetch'
+
+const interceptor = new FetchInterceptor()
+
+const httpServer = new HttpServer((app) => {
+  app.post('/resource', express.text(), (req, res) =>
+    res.send(`received: ${req.body}`)
+  )
+})
+
+beforeAll(async () => {
+  interceptor.apply()
+  await httpServer.listen()
+})
+
+afterEach(() => {
+  interceptor['emitter'].removeAllListeners()
+})
+
+afterAll(async () => {
+  interceptor.dispose()
+  await httpServer.close()
+})
+
+it('does not mark request body as used for request with no listeners', async () => {
+  const request = new Request(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+  const responsePromise = fetch(request)
+  const bodyUsedAfterFetch = request.bodyUsed
+
+  await interceptor['emitter'].untilIdle('request')
+  const bodyUsedAfterListeners = request.bodyUsed
+
+  const response = await responsePromise
+  const bodyUsedAfterResponse = request.bodyUsed
+
+  expect(bodyUsedAfterFetch).toBe(false)
+  expect(bodyUsedAfterListeners).toBe(false)
+  expect(bodyUsedAfterResponse).toBe(false)
+
+  expect(await response.text()).toBe('received: Hello server')
+})
+
+it('does not mark request body as used for request with a bypass listener', async () => {
+  interceptor.on('request', ({ request }) => {
+    return
+  })
+
+  const request = new Request(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+  const responsePromise = fetch(request)
+  const bodyUsedAfterFetch = request.bodyUsed
+
+  await interceptor['emitter'].untilIdle('request')
+  const bodyUsedAfterListeners = request.bodyUsed
+
+  const response = await responsePromise
+  const bodyUsedAfterResponse = request.bodyUsed
+
+  expect(bodyUsedAfterFetch).toBe(false)
+  expect(bodyUsedAfterListeners).toBe(false)
+  expect(bodyUsedAfterResponse).toBe(false)
+
+  expect(await response.text()).toBe('received: Hello server')
+})
+
+it('does not mark request body as used for request with a mocked response listener', async () => {
+  interceptor.on('request', ({ request }) => {
+    // The request body remains unused because the listener
+    // never read it. Nothing else should.
+    request.respondWith(new Response('Mocked response'))
+  })
+
+  const request = new Request(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+  const responsePromise = fetch(request)
+  const bodyUsedAfterFetch = request.bodyUsed
+
+  await interceptor['emitter'].untilIdle('request')
+  const bodyUsedAfterListeners = request.bodyUsed
+
+  const response = await responsePromise
+  const bodyUsedAfterResponse = request.bodyUsed
+
+  expect(bodyUsedAfterFetch).toBe(false)
+  expect(bodyUsedAfterListeners).toBe(false)
+  expect(bodyUsedAfterResponse).toBe(false)
+
+  expect(await response.text()).toBe('Mocked response')
+})
+
+it('marks request body as used if the mocked response listener reads it', async () => {
+  interceptor.on('request', async ({ request }) => {
+    const text = await request.text()
+
+    // The request body remains unused because the listener
+    // never read it. Nothing else should.
+    request.respondWith(new Response(`mocked: ${text}`))
+  })
+
+  const request = new Request(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+  const responsePromise = fetch(request)
+  const bodyUsedAfterFetch = request.bodyUsed
+
+  await interceptor['emitter'].untilIdle('request')
+  const bodyUsedAfterListeners = request.bodyUsed
+
+  const response = await responsePromise
+  const bodyUsedAfterResponse = request.bodyUsed
+
+  expect(bodyUsedAfterFetch).toBe(false)
+  // Since the request listener reads the request body,
+  // it should only be marked as read after the listeners are done.
+  expect(bodyUsedAfterListeners).toBe(true)
+  expect(bodyUsedAfterResponse).toBe(true)
+
+  expect(await response.text()).toBe('mocked: Hello server')
+})