fix: cypress removes custom status text/reason phrase from http respo…

…nse (#22061)

packages/proxy/lib/http/response-middleware.ts

@@ -509,6 +509,12 @@ const MaybeSendRedirectToClient: ResponseMiddleware = function () {
 
 const CopyResponseStatusCode: ResponseMiddleware = function () {
   this.res.status(Number(this.incomingRes.statusCode))
+  // Set custom status message/reason phrase from http response
+  // https://github.com/cypress-io/cypress/issues/16973
+  if (this.incomingRes.statusMessage) {
+    this.res.statusMessage = this.incomingRes.statusMessage
+  }
+
   this.next()
 }
 

packages/server/test/integration/http_requests_spec.js

@@ -3783,6 +3783,65 @@ describe('Routes', () => {
       })
     })
 
+    // Set custom status message/reason phrase from http response
+    // https://github.com/cypress-io/cypress/issues/16973
+    it('set custom status message when reason phrase is set', function () {
+      nock(this.server.remoteStates.current().origin)
+      .post('/companies/validate', {
+        payload: { name: 'Brian' },
+      })
+      .reply(400, function (uri, requestBody) {
+        this.req.response.statusMessage = 'This is the custom status message'
+
+        return {
+          status: 400,
+          message: 'This is the reply body',
+        }
+      })
+
+      return this.rp({
+        method: 'POST',
+        url: 'http://localhost:8000/companies/validate',
+        json: true,
+        body: {
+          payload: { name: 'Brian' },
+        },
+        headers: {
+          'x-cypress-status': '400',
+        },
+      })
+      .then((res) => {
+        expect(res.statusCode).to.eq(400)
+        expect(res.statusMessage).to.eq('This is the custom status message')
+      })
+    })
+
+    // use default status message/reason phrase correspond to status code, from http response
+    // https://github.com/cypress-io/cypress/issues/16973
+    it('uses default status message when reason phrase is not set', function () {
+      nock(this.server.remoteStates.current().origin)
+      .post('/companies/validate', {
+        payload: { name: 'Brian' },
+      })
+      .reply(400)
+
+      return this.rp({
+        method: 'POST',
+        url: 'http://localhost:8000/companies/validate',
+        json: true,
+        body: {
+          payload: { name: 'Brian' },
+        },
+        headers: {
+          'x-cypress-status': '400',
+        },
+      })
+      .then((res) => {
+        expect(res.statusCode).to.eq(400)
+        expect(res.statusMessage).to.eq('Bad Request')
+      })
+    })
+
     it('hands back 201 status codes', function () {
       nock(this.server.remoteStates.current().origin)
       .post('/companies/validate', {