test: add unit test to verify content-length behavior on modified req…

…uests

packages/net-stubbing/package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "build-prod": "tsc --project .",
     "clean-deps": "rimraf node_modules",
-    "test": "CYPRESS_INTERNAL_ENV=test mocha -r @packages/ts/register --reporter mocha-multi-reporters --reporter-options configFile=../../mocha-reporter-config.json --exit test/unit/*",
+    "test": "CYPRESS_INTERNAL_ENV=test mocha -r @packages/ts/register --reporter mocha-multi-reporters --reporter-options configFile=../../mocha-reporter-config.json --exit test/unit/**/*",
     "lint": "eslint --ext .ts,.json, ."
   },
   "dependencies": {

packages/net-stubbing/test/unit/middleware/request-spec.ts

@@ -0,0 +1,80 @@
+import { expect } from 'chai'
+import sinon from 'sinon'
+import { InterceptRequest } from '../../../lib/server/middleware/request'
+import { state as NetStubbingState } from '../../../lib/server/state'
+
+describe('request', () => {
+  context('InterceptedRequest', () => {
+    // @see https://github.com/cypress-io/cypress/issues/24407
+    it('does not set the content-length header if the header was not there to begin with on the original request', async () => {
+      const socket = {
+        toDriver: sinon.stub(),
+      }
+      const state = NetStubbingState()
+
+      const beforeRequestData = {
+        body: 'stubbed_body',
+        proxiedUrl: 'https://foobar.com',
+        url: 'https://foobar.com',
+      }
+
+      const afterRequestData = {
+        ...beforeRequestData,
+        body: '',
+        headers: {},
+      }
+
+      // using a ES6 proxy to intercept the promise assignment on pendingEventHandlers.
+      // this way, we can resolve the event immediately
+      const pendingEventProxy = new Proxy(state.pendingEventHandlers, {
+        get (target, prop, receiver) {
+          // @ts-expect-error
+          return Reflect.get(...arguments)
+        },
+        set (obj, prop, value) {
+          // @ts-expect-error
+          const setProp = Reflect.set(...arguments)
+
+          // invoke the promise function immediately
+          if (typeof value === 'function') {
+            value({
+              changedData: afterRequestData,
+              stopPropagation: false,
+            })
+          }
+
+          return setProp
+        },
+      })
+
+      state.pendingEventHandlers = pendingEventProxy
+
+      const request = {
+        req: {
+          ...beforeRequestData,
+          headers: {},
+          matchingRoutes: [
+            {
+              id: '1',
+              hasInterceptor: true,
+              routeMatcher: {},
+            },
+          ],
+          pipe: sinon.stub(),
+        },
+        res: {
+          once: sinon.stub(),
+        },
+        socket,
+        debug: sinon.stub(),
+        netStubbingState: state,
+        next: sinon.stub(),
+        onError: sinon.stub(),
+        onResponse: sinon.stub(),
+      }
+
+      await InterceptRequest.call(request)
+      expect(request.req.headers['content-length']).to.be.undefined
+    })
+  })
+})