test(fetch): add "bodyUsed" compliance (#403)

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

@@ -0,0 +1,78 @@
+import { it, expect, beforeAll, afterEach, afterAll } from 'vitest'
+import * as express from 'express'
+import { DeferredPromise } from '@open-draft/deferred-promise'
+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('request body is unused in the listener when using Request argument', async () => {
+  const requestInListenerPromise = new DeferredPromise<Request>()
+  interceptor.on('request', ({ request }) => {
+    requestInListenerPromise.resolve(request)
+  })
+
+  const request = new Request(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+  const bodyUsedBeforeFetch = request.bodyUsed
+
+  const responsePromise = fetch(request)
+  const bodyUsedAfterFetch = request.bodyUsed
+
+  const requestInListener = await requestInListenerPromise
+  const bodyUsedInListener = requestInListener.bodyUsed
+
+  const response = await responsePromise
+  const bodyUsedAfterResponse = request.bodyUsed
+
+  expect(bodyUsedBeforeFetch).toBe(false)
+  expect(bodyUsedInListener).toBe(false)
+  // Fetch reads the request body in order to send it.
+  expect(bodyUsedAfterFetch).toBe(true)
+  expect(bodyUsedAfterResponse).toBe(true)
+
+  expect(await response.text()).toBe('received: Hello server')
+})
+
+it('request body is unused in the listener when using input and init arguments', async () => {
+  const requestInListenerPromise = new DeferredPromise<Request>()
+  interceptor.on('request', ({ request }) => {
+    requestInListenerPromise.resolve(request)
+  })
+
+  const responsePromise = fetch(httpServer.http.url('/resource'), {
+    method: 'POST',
+    body: 'Hello server',
+  })
+
+  const requestInListener = await requestInListenerPromise
+  const bodyUsedInListener = requestInListener.bodyUsed
+
+  const response = await responsePromise
+
+  expect(bodyUsedInListener).toBe(false)
+
+  expect(await response.text()).toBe('received: Hello server')
+})