fix: Agent.Options.factory should accept URL object or string as para…

…meter (nodejs#2295)

test/agent.js

@@ -10,6 +10,7 @@ const {
   request,
   stream,
   pipeline,
+  Pool,
   setGlobalDispatcher,
   getGlobalDispatcher
 } = require('../')
@@ -267,6 +268,78 @@ test('multiple connections', t => {
   })
 })
 
+test('agent factory supports URL parameter', (t) => {
+  t.plan(2)
+
+  const noopHandler = {
+    onConnect () {},
+    onHeaders () {},
+    onData () {},
+    onComplete () {
+      server.close()
+    },
+    onError (err) {
+      throw err
+    }
+  }
+
+  const dispatcher = new Agent({
+    factory: (origin, opts) => {
+      t.ok(origin instanceof URL)
+      return new Pool(origin, opts)
+    }
+  })
+
+  const server = http.createServer((req, res) => {
+    res.setHeader('Content-Type', 'text/plain')
+    res.end('asd')
+  })
+
+  server.listen(0, () => {
+    t.doesNotThrow(() => dispatcher.dispatch({
+      origin: new URL(`http://localhost:${server.address().port}`),
+      path: '/',
+      method: 'GET'
+    }, noopHandler))
+  })
+})
+
+test('agent factory supports string parameter', (t) => {
+  t.plan(2)
+
+  const noopHandler = {
+    onConnect () {},
+    onHeaders () {},
+    onData () {},
+    onComplete () {
+      server.close()
+    },
+    onError (err) {
+      throw err
+    }
+  }
+
+  const dispatcher = new Agent({
+    factory: (origin, opts) => {
+      t.ok(typeof origin === 'string')
+      return new Pool(origin, opts)
+    }
+  })
+
+  const server = http.createServer((req, res) => {
+    res.setHeader('Content-Type', 'text/plain')
+    res.end('asd')
+  })
+
+  server.listen(0, () => {
+    t.doesNotThrow(() => dispatcher.dispatch({
+      origin: `http://localhost:${server.address().port}`,
+      path: '/',
+      method: 'GET'
+    }, noopHandler))
+  })
+})
+
 test('with globalAgent', t => {
   t.plan(6)
   const wanted = 'payload'

types/agent.d.ts

@@ -17,7 +17,7 @@ declare class Agent extends Dispatcher{
 declare namespace Agent {
   export interface Options extends Pool.Options {
     /** Default: `(origin, opts) => new Pool(origin, opts)`. */
-    factory?(origin: URL, opts: Object): Dispatcher;
+    factory?(origin: string | URL, opts: Object): Dispatcher;
     /** Integer. Default: `0` */
     maxRedirections?: number;