fix: add "address()" on mock Socket (#549)

Co-authored-by: Artem Zakharchenko <[email protected]>

src/interceptors/ClientRequest/MockHttpSocket.ts

@@ -124,6 +124,7 @@ export class MockHttpSocket extends MockSocket {
    */
   public passthrough(): void {
     const socket = this.createConnection()
+    this.address = socket.address.bind(socket)
 
     // Flush the buffered "socket.write()" calls onto
     // the original socket instance (i.e. write request body).
@@ -218,7 +219,9 @@ export class MockHttpSocket extends MockSocket {
 
     httpHeaders.push(
       Buffer.from(
-        `HTTP/1.1 ${response.status} ${response.statusText || STATUS_CODES[response.status]}\r\n`
+        `HTTP/1.1 ${response.status} ${
+          response.statusText || STATUS_CODES[response.status]
+        }\r\n`
       )
     )
 
@@ -298,7 +301,20 @@ export class MockHttpSocket extends MockSocket {
   }
 
   private mockConnect(): void {
-    this.emit('lookup', null, '::1', 6, this.connectionOptions.host)
+    const addressInfo = {
+      address: '127.0.0.1',
+      family: 'IPv4',
+      port: this.connectionOptions.port,
+    }
+    // Return fake address information for the socket.
+    this.address = () => addressInfo
+    this.emit(
+      'lookup',
+      null,
+      addressInfo.address,
+      addressInfo.family === 'IPv6' ? 6 : 4,
+      this.connectionOptions.host
+    )
     this.emit('connect')
     this.emit('ready')
 

test/modules/http/compliance/http.test.ts

@@ -163,3 +163,45 @@ it('mocks response to a non-existing host', async () => {
   expect(await text()).toBe('howdy, john')
   expect(requestListener).toHaveBeenCalledTimes(1)
 })
+
+it('returns socket address for a mocked request', async () => {
+  interceptor.on('request', async ({ request }) => {
+    request.respondWith(new Response())
+  })
+
+  const addressPromise = new DeferredPromise<object>()
+  const request = http.get('http://example.com')
+  request.once('socket', (socket) => {
+    socket.once('connect', () => {
+      addressPromise.resolve(socket.address())
+    })
+  })
+
+  await expect(addressPromise).resolves.toEqual({
+    address: '127.0.0.1',
+    family: 'IPv4',
+    port: 80,
+  })
+})
+
+it('returns socket address for a bypassed request', async () => {
+  const addressPromise = new DeferredPromise<object>()
+  const request = http.get(httpServer.http.url('/user'))
+  request.once('socket', (socket) => {
+    socket.once('connect', () => {
+      addressPromise.resolve(socket.address())
+    })
+  })
+
+  await waitForClientRequest(request)
+
+  await expect(addressPromise).resolves.toEqual({
+    address: httpServer.http.address.host,
+    family: 'IPv4',
+    /**
+     * @fixme Looks like every "http" request has an agent set.
+     * That agent, for some reason, wants to connect to a different port.
+     */
+    port: expect.any(Number),
+  })
+})