Failing test: escaping inconsistent to requestInterceptor

For: #1220

`npm t` gives:
>  Error: Expected 'percent-twentyseven' to equal 'quote'

* Request has a quote (') in it
* The interceptor sees req.url ending in quote (') which is a perfectly valid thing for a URL to end in…
* However, the xmock  shows the actual URL ends in /%27

test/index.js

@@ -2,6 +2,9 @@ import expect, {createSpy} from 'expect'
 import xmock from 'xmock'
 import Swagger from '../src/index'
 
+// only used for the WORKAROUND (see below)
+import url from 'url'
+
 describe('constructor', () => {
   afterEach(function () {
     expect.restoreSpies()
@@ -530,6 +533,8 @@ describe('constructor', () => {
             $ref: 'http://petstore.swagger.io/v2/ref.json#b'
           }
         ))
+        .get('http://petstore.swagger.io/v2/user/\'', () => ({u: 'quote'}))  // Not hit, this is the URL the interceptor sees.
+        .get('http://petstore.swagger.io/v2/user/%27', () => ({u: 'percent-twentyseven'}))  // We actually get this.
     })
 
     it('should support request interceptor', function (cb) {
@@ -601,5 +606,22 @@ describe('constructor', () => {
         cb()
       }).catch(cb)
     })
+
+    it('should give the interceptor the URL which actually hits the network', () =>
+      new Swagger({
+        url: 'http://petstore.swagger.io/v2/swagger.json',
+        requestInterceptor: (req) => {
+          if (req.url === 'http://petstore.swagger.io/v2/swagger.json') {
+            return req // skip this
+          }
+          expect(req.url).toEqual('http://petstore.swagger.io/v2/user/\'') // Not percent-escaped
+          return req
+        }
+      }).then(client =>
+        client.apis.user.getUserByName({username: '\''}).then((data) => {
+          expect(data.body.u).toEqual('quote')  // not percent escaped
+        })
+      )
+    )
   })
 })