diff --git a/lib/cli.js b/lib/cli.js
index 335aabc51..520dd43d3 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -1,6 +1,6 @@
 var path = require('path')
 var optimist = require('optimist')
-var fs = require('fs')
+var fs = require('graceful-fs')
 
 var Server = require('./server')
 var helper = require('./helper')
diff --git a/lib/completion.js b/lib/completion.js
index 4611c776b..4ffe3b7a8 100644
--- a/lib/completion.js
+++ b/lib/completion.js
@@ -130,7 +130,7 @@ var completion = function () {
   }
 
   // just print out the karma-completion.sh
-  var fs = require('fs')
+  var fs = require('graceful-fs')
   var path = require('path')
 
   fs.readFile(path.resolve(__dirname, '../scripts/karma-completion.sh'), 'utf8', function (err, data) {
diff --git a/lib/constants.js b/lib/constants.js
index 0bafe9e61..da974f0d2 100644
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -1,4 +1,4 @@
-var fs = require('fs')
+var fs = require('graceful-fs')
 
 var pkg = JSON.parse(fs.readFileSync(__dirname + '/../package.json').toString())
 
diff --git a/lib/file-list.js b/lib/file-list.js
index f02f2f77e..c73b98ca5 100644
--- a/lib/file-list.js
+++ b/lib/file-list.js
@@ -12,7 +12,7 @@ var from = require('core-js/library/fn/array/from')
 var Promise = require('bluebird')
 var mm = require('minimatch')
 var Glob = require('glob').Glob
-var fs = Promise.promisifyAll(require('fs'))
+var fs = Promise.promisifyAll(require('graceful-fs'))
 var pathLib = require('path')
 
 var File = require('./file')
diff --git a/lib/helper.js b/lib/helper.js
index f414dceef..04bafa6fb 100644
--- a/lib/helper.js
+++ b/lib/helper.js
@@ -1,4 +1,4 @@
-var fs = require('fs')
+var fs = require('graceful-fs')
 var path = require('path')
 var _ = require('lodash')
 var useragent = require('useragent')
diff --git a/lib/init/formatters.js b/lib/init/formatters.js
index 78cd6fe79..50251b16a 100644
--- a/lib/init/formatters.js
+++ b/lib/init/formatters.js
@@ -1,4 +1,4 @@
-var fs = require('fs')
+var fs = require('graceful-fs')
 var util = require('util')
 
 var JS_TEMPLATE_PATH = __dirname + '/../../config.tpl.js'
diff --git a/lib/plugin.js b/lib/plugin.js
index e91e21e41..80e0b6d1b 100644
--- a/lib/plugin.js
+++ b/lib/plugin.js
@@ -1,4 +1,4 @@
-var fs = require('fs')
+var fs = require('graceful-fs')
 var path = require('path')
 
 var helper = require('./helper')
diff --git a/lib/temp_dir.js b/lib/temp_dir.js
index 5d6ac3749..6543c2407 100644
--- a/lib/temp_dir.js
+++ b/lib/temp_dir.js
@@ -1,5 +1,5 @@
 var path = require('path')
-var fs = require('fs')
+var fs = require('graceful-fs')
 var os = require('os')
 var rimraf = require('rimraf')
 var log = require('./logger').create('temp-dir')
diff --git a/lib/web-server.js b/lib/web-server.js
index 89b5165bd..4dfc248c7 100644
--- a/lib/web-server.js
+++ b/lib/web-server.js
@@ -1,4 +1,4 @@
-var fs = require('fs')
+var fs = require('graceful-fs')
 var http = require('http')
 var https = require('https')
 var path = require('path')
diff --git a/package.json b/package.json
index c889fafca..bdb3e565c 100644
--- a/package.json
+++ b/package.json
@@ -324,6 +324,7 @@
     "load-grunt-tasks": "^3.1.0",
     "mkdirp": "^0.5.0",
     "mocha": "^2.2.5",
+    "mock-fs": "^3.6.0",
     "mocks": "^0.0.15",
     "phantomjs": "^1.9.19",
     "proxyquire": "^1.5.0",
diff --git a/test/unit/file-list.spec.js b/test/unit/file-list.spec.js
index 69bb1589f..7e22c1652 100644
--- a/test/unit/file-list.spec.js
+++ b/test/unit/file-list.spec.js
@@ -36,11 +36,15 @@ var MG = {
   }
 }
 var mockFs = mocks.fs.create({
-  some: {'0.js': mocks.fs.file('2012-04-04'),
+  some: {
+    '0.js': mocks.fs.file('2012-04-04'),
     'a.js': mocks.fs.file('2012-04-04'),
     'b.js': mocks.fs.file('2012-05-05'),
-  'd.js': mocks.fs.file('2012-05-05')},
-  folder: {'x.js': mocks.fs.file(0)},
+    'd.js': mocks.fs.file('2012-05-05')
+  },
+  folder: {
+    'x.js': mocks.fs.file(0)
+  },
   'a.txt': mocks.fs.file(0),
   'b.txt': mocks.fs.file(0),
   'c.txt': mocks.fs.file(0),
@@ -77,7 +81,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
     })
 
@@ -207,7 +211,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
 
       list = new List(patterns('/some/*.js', '*.txt'), [], emitter, preprocess)
@@ -244,7 +248,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
 
       list = new List(patterns('/some/*.js', '*.txt'), [], emitter, preprocess, 100)
@@ -414,7 +418,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
 
       list = new List(patterns('/some/*.js', '*.txt'), ['/secret/*.txt'], emitter, preprocess)
@@ -527,7 +531,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
 
       mockFs._touchFile('/some/a.js', '2012-04-04')
@@ -620,7 +624,7 @@ describe('FileList', () => {
         helper: helper,
         glob: glob,
         path: pathLib.posix || pathLib/* for node 0.10 */,
-        fs: mockFs
+        'graceful-fs': mockFs
       })
 
       modified = sinon.stub()
@@ -687,7 +691,7 @@ describe('FileList', () => {
       List = proxyquire('../../lib/file-list', {
         helper: helper,
         glob: glob,
-        fs: mockFs,
+        'graceful-fs': mockFs,
         path: pathLib.posix || pathLib/* for node 0.10 */,
         bluebird: Promise
       })
diff --git a/test/unit/helper.spec.js b/test/unit/helper.spec.js
index 817ca7d6f..7a10a81e4 100644
--- a/test/unit/helper.spec.js
+++ b/test/unit/helper.spec.js
@@ -217,7 +217,8 @@ describe('helper', () => {
     })
 
     // load file under test
-    var m = loadFile(__dirname + '/../../lib/helper.js', {fs: fs, lodash: require('lodash')})
+    var m = loadFile(__dirname + '/../../lib/helper.js', {'graceful-fs': fs, lodash: require('lodash')})
+
     var mkdirIfNotExists = m.exports.mkdirIfNotExists
 
     it('should not do anything, if dir already exists', done => {
diff --git a/test/unit/web-server.spec.js b/test/unit/web-server.spec.js
index 7d311ba1e..17327c5de 100644
--- a/test/unit/web-server.spec.js
+++ b/test/unit/web-server.spec.js
@@ -14,7 +14,7 @@ describe('web-server', () => {
   var _mocks = {}
   var _globals = {__dirname: '/karma/lib'}
 
-  _mocks.fs = mocks.fs.create({
+  _mocks['graceful-fs'] = mocks.fs.create({
     karma: {
       static: {
         'client.html': mocks.fs.file(0, 'CLIENT HTML')