tests: entire test suite uses express 4.12.2

package.json

@@ -17,6 +17,7 @@
     "vary": "~1.0.0"
   },
   "devDependencies": {
+    "express": "~4.12.2",
     "istanbul": "0.3.7",
     "mocha": "2.2.1",
     "supertest": "~0.15.0"

test/compression.js

@@ -1,7 +1,7 @@
 var assert = require('assert')
 var bytes = require('bytes');
 var crypto = require('crypto');
-var http = require('http');
+var express = require('express');
 var request = require('supertest');
 
 var compression = require('..');
@@ -458,7 +458,7 @@ describe('compression()', function(){
     })
 
     it('should return false on empty response', function (done) {
-      var server = http.createServer(function (req, res) {
+      var server = express().use(function (req, res) {
         res.end(String(compression.filter(req, res)))
       })
 
@@ -468,7 +468,7 @@ describe('compression()', function(){
     })
 
     it('should return true for "text/plain"', function (done) {
-      var server = http.createServer(function (req, res) {
+      var server = express().use(function (req, res) {
         res.setHeader('Content-Type', 'text/plain')
         res.end(String(compression.filter(req, res)))
       })
@@ -479,7 +479,7 @@ describe('compression()', function(){
     })
 
     it('should return false for "application/x-bogus"', function (done) {
-      var server = http.createServer(function (req, res) {
+      var server = express().use(function (req, res) {
         res.setHeader('Content-Type', 'application/x-bogus')
         res.end(String(compression.filter(req, res)))
       })
@@ -605,18 +605,9 @@ describe('compression()', function(){
 })
 
 function createServer(opts, fn) {
-  var _compression = compression(opts)
-  return http.createServer(function (req, res) {
-    _compression(req, res, function (err) {
-      if (err) {
-        res.statusCode = err.status || 500
-        res.end(err.message)
-        return;
-      }
-
-      fn(req, res)
-    })
-  })
+  return express()
+  .use(compression(opts))
+  .use(fn)
 }
 
 function shouldHaveBodyLength(length) {