diff --git a/.babelrc b/.babelrc
deleted file mode 100644
index 3d36bc0fb..000000000
--- a/.babelrc
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "presets": ["es2015"],
-  "retainLines": true
-}
diff --git a/.travis.yml b/.travis.yml
index 0658f7ab1..95c0c269f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,9 +2,9 @@ sudo: false
 language: node_js
 node_js:
   - 4
-  - 5
-  - 7
+  - 6
   - 8
+  - 9
 
 env:
   global:
@@ -14,7 +14,7 @@ env:
 matrix:
   fast_finish: true
   include:
-    - node_js: "6"
+    - node_js: "8"
       env: VALIDATE_COMMIT_MSG=true LINT=true
 
 before_install:
diff --git a/appveyor.yml b/appveyor.yml
index 2068d8947..150f49eb8 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -3,9 +3,7 @@ version: "{build}"
 environment:
   matrix:
     - nodejs_version: "4"
-    - nodejs_version: "5"
     - nodejs_version: "6"
-    - nodejs_version: "7"
     - nodejs_version: "8"
 
 matrix:
diff --git a/docs/config/01-configuration-file.md b/docs/config/01-configuration-file.md
index 6deb8c1f6..742f4509a 100644
--- a/docs/config/01-configuration-file.md
+++ b/docs/config/01-configuration-file.md
@@ -522,6 +522,8 @@ See [plugins] for more information.
 
 **Description:** The port where the web server will be listening.
 
+If the defined port is already in use, karma will automatically increase its value in steps of 1 until a free port is found.
+
 
 ## processKillTimeout
 **Type:** Number
diff --git a/gruntfile.js b/gruntfile.js
index e92844ff4..0a1b6f1ce 100644
--- a/gruntfile.js
+++ b/gruntfile.js
@@ -31,7 +31,6 @@ module.exports = function (grunt) {
     },
     mochaTest: {
       options: {
-        require: 'babel-register',
         reporter: 'dot',
         ui: 'bdd',
         quiet: false,
diff --git a/lib/config.js b/lib/config.js
index f41860bb9..e77fecfd4 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -365,7 +365,6 @@ var CONFIG_SYNTAX_HELP = '  module.exports = function(config) {\n' +
 var parseConfig = function (configFilePath, cliOptions) {
   var configModule
   if (configFilePath) {
-    log.debug('Loading config %s', configFilePath)
 
     try {
       configModule = require(configFilePath)
@@ -397,7 +396,6 @@ var parseConfig = function (configFilePath, cliOptions) {
       return process.exit(1)
     }
   } else {
-    log.debug('No config file specified.')
     // if no config file path is passed, we define a dummy config module.
     configModule = function () {}
   }
@@ -441,6 +439,12 @@ var parseConfig = function (configFilePath, cliOptions) {
   // configure the logger as soon as we can
   logger.setup(config.logLevel, config.colors, config.loggers)
 
+  if (configFilePath) {
+    log.debug('Loading config %s', configFilePath)
+  } else {
+    log.debug('No config file specified.')
+  }
+
   return normalizeConfig(config, configFilePath)
 }
 
diff --git a/lib/file-list.js b/lib/file-list.js
index 2645e855b..726c920ae 100644
--- a/lib/file-list.js
+++ b/lib/file-list.js
@@ -7,9 +7,6 @@
 // Dependencies
 // ------------
 
-var Map = require('core-js/library/fn/map')
-var Set = require('core-js/library/fn/set')
-var from = require('core-js/library/fn/array/from')
 var Promise = require('bluebird')
 var mm = require('minimatch')
 var Glob = require('glob').Glob
@@ -120,7 +117,7 @@ List.prototype._findFile = function (path, pattern) {
   if (!path || !pattern) return
   if (!this.buckets.has(pattern.pattern)) return
 
-  return _.find(from(this.buckets.get(pattern.pattern)), function (file) {
+  return _.find(Array.from(this.buckets.get(pattern.pattern)), function (file) {
     return file.originalPath === path
   })
 }
@@ -229,7 +226,7 @@ Object.defineProperty(List.prototype, 'files', {
     }
 
     var expandPattern = function (p) {
-      return from(self.buckets.get(p.pattern) || []).sort(byPath)
+      return Array.from(self.buckets.get(p.pattern) || []).sort(byPath)
     }
 
     var served = this._patterns.filter(function (pattern) {
diff --git a/lib/launcher.js b/lib/launcher.js
index be15dcf56..56292e1bf 100644
--- a/lib/launcher.js
+++ b/lib/launcher.js
@@ -43,6 +43,7 @@ var Launcher = function (server, emitter, injector) {
   this.launchSingle = function (protocol, hostname, port, urlRoot, upstreamProxy, processKillTimeout) {
     var self = this
     return function (name) {
+      name = (name + '').trim();
       if (upstreamProxy) {
         protocol = upstreamProxy.protocol
         hostname = upstreamProxy.hostname
diff --git a/lib/middleware/source_files.js b/lib/middleware/source_files.js
index 34395f63d..46fbfe0c6 100644
--- a/lib/middleware/source_files.js
+++ b/lib/middleware/source_files.js
@@ -1,4 +1,3 @@
-var from = require('core-js/library/fn/array/from')
 var querystring = require('querystring')
 var _ = require('lodash')
 
@@ -8,17 +7,17 @@ var log = logger.create('middleware:source-files')
 
 // Files is a Set
 var findByPath = function (files, path) {
-  return _.find(from(files), function (file) {
+  return _.find(Array.from(files), function (file) {
     return file.path === path
   })
 }
 
 var composeUrl = function (url, basePath, urlRoot, mustEscape) {
   return (mustEscape ? querystring.unescape(url) : url)
-            .replace(urlRoot, '/')
-            .replace(/\?.*$/, '')
-            .replace(/^\/absolute/, '')
-            .replace(/^\/base/, basePath)
+    .replace(urlRoot, '/')
+    .replace(/\?.*$/, '')
+    .replace(/^\/absolute/, '')
+    .replace(/^\/base/, basePath)
 }
 
 // Source Files middleware is responsible for serving all the source files under the test.
diff --git a/lib/reporter.js b/lib/reporter.js
index 75d7bb5a6..546571db6 100644
--- a/lib/reporter.js
+++ b/lib/reporter.js
@@ -1,7 +1,6 @@
 var util = require('util')
 var resolve = require('url').resolve
 var SourceMapConsumer = require('source-map').SourceMapConsumer
-var WeakMap = require('core-js/es6/weak-map')
 var _ = require('lodash')
 
 var log = require('./logger').create('reporter')
diff --git a/package.json b/package.json
index f00fd4aa8..c6faad3a1 100644
--- a/package.json
+++ b/package.json
@@ -350,25 +350,23 @@
     "range-parser": "^1.2.0",
     "rimraf": "^2.6.0",
     "safe-buffer": "^5.0.1",
-    "socket.io": "2.0.3",
-    "source-map": "^0.5.3",
-    "tmp": "0.0.31",
+    "socket.io": "2.0.4",
+    "source-map": "^0.6.1",
+    "tmp": "0.0.33",
     "useragent": "^2.1.12"
   },
   "devDependencies": {
     "LiveScript": "^1.3.0",
-    "babel": "^6.23.0",
-    "babel-preset-es2015": "^6.22.0",
-    "babel-register": "^6.23.0",
-    "chai": "^3.3.0",
-    "chai-as-promised": "^6.0.0",
+    "babel-core": "^6.26.0",
+    "chai": "^4.1.2",
+    "chai-as-promised": "^7.1.1",
     "chai-subset": "^1.2.2",
-    "coffee-script": "^1.12.4",
-    "cucumber": "^2.2.0",
-    "eslint": "^3.15.0",
+    "coffeescript": "^1.12.7",
+    "cucumber": "^3.1.0",
+    "eslint": "^4.11.0",
     "eslint-config-standard": "^10.2.1",
     "eslint-plugin-import": "^2.2.0",
-    "eslint-plugin-node": "^4.2.2",
+    "eslint-plugin-node": "^5.2.1",
     "eslint-plugin-promise": "^3.4.2",
     "eslint-plugin-react": "^7.0.1",
     "eslint-plugin-standard": "^3.0.1",
@@ -380,12 +378,12 @@
     "grunt-contrib-watch": "^1.0.0",
     "grunt-conventional-changelog": "^6.0.1",
     "grunt-conventional-github-releaser": "^1.0.0",
-    "grunt-cucumberjs": "^1.0.0",
-    "grunt-eslint": "^19.0.0",
+    "grunt-cucumberjs": "^2.0.2",
+    "grunt-eslint": "^20.1.0",
     "grunt-mocha-test": "^0.13.2",
     "grunt-npm": "0.0.2",
     "http2": "^3.3.6",
-    "husky": "^0.13.1",
+    "husky": "^0.14.3",
     "jasmine-core": "^2.3.4",
     "json3": "^3.3.2",
     "karma-browserify": "^5.0.1",
@@ -411,13 +409,13 @@
     "karma-script-launcher": "^1.0.0",
     "load-grunt-tasks": "^3.1.0",
     "mkdirp": "^0.5.0",
-    "mocha": "^3.2.0",
+    "mocha": "^4.0.1",
     "mocks": "^0.0.15",
     "phantomjs-prebuilt": "^2.1.3",
     "proxyquire": "^1.7.11",
     "qunitjs": "^2.1.1",
     "requirejs": "^2.1.20",
-    "sinon": "^2.2.0",
+    "sinon": "^4.1.2",
     "sinon-chai": "^2.7.0",
     "supertest": "^3.0.0",
     "timer-shim": "^0.3.0",
@@ -434,7 +432,7 @@
   "version": "1.7.1",
   "license": "MIT",
   "scripts": {
-    "lint": "eslint client/**/*.js common/**/*.js context/**/*.js gruntfile.js wallaby.js lib/**/*.js test/**/*.js static/debug.js",
+    "lint": "eslint client/**/*.js common/**/*.js context/**/*.js gruntfile.js wallaby.js lib/**/*.js test/unit/**/*.js test/client/*.js test/e2e/**/*.js static/debug.js",
     "test": "grunt test",
     "build": "grunt build",
     "test:appveyor": "grunt test-appveyor",
diff --git a/test/e2e/step_definitions/core_steps.js b/test/e2e/step_definitions/core_steps.js
index 96e7e8b00..dbd638d0b 100644
--- a/test/e2e/step_definitions/core_steps.js
+++ b/test/e2e/step_definitions/core_steps.js
@@ -1,13 +1,17 @@
-var {defineSupportCode} = require('cucumber')
+var cucumber = require('cucumber')
+var fs = require('fs')
+var path = require('path')
+var ref = require('child_process')
+var exec = ref.exec
+var spawn = ref.spawn
+var rimraf = require('rimraf')
+var stopper = require('../../../lib/stopper')
 
-defineSupportCode(function ({defineParameterType, Given, Then, When}) {
-  var fs = require('fs')
-  var path = require('path')
-  var ref = require('child_process')
-  var exec = ref.exec
-  var spawn = ref.spawn
-  var rimraf = require('rimraf')
-  var stopper = require('../../../lib/stopper')
+cucumber.defineSupportCode((a) => {
+  var When = a.When
+  var Then = a.Then
+  var Given = a.Given
+  var defineParameterType = a.defineParameterType
 
   var baseDir = fs.realpathSync(path.join(__dirname, '/../../..'))
   var tmpDir = path.join(baseDir, 'tmp', 'sandbox')
@@ -28,13 +32,94 @@ defineSupportCode(function ({defineParameterType, Given, Then, When}) {
     }
   }
 
+  function execKarma (command, level, proxyPort, proxyPath, callback) {
+    level = level || 'warn'
+
+    var startProxy = (done) => {
+      if (proxyPort) {
+        this.proxy.start(proxyPort, proxyPath, done)
+      } else {
+        done()
+      }
+    }
+
+    startProxy((err) => {
+      if (err) {
+        return callback.fail(err)
+      }
+
+      this.writeConfigFile(tmpDir, tmpConfigFile, (err, hash) => {
+        if (err) {
+          return callback.fail(new Error(err))
+        }
+        var configFile = path.join(tmpDir, hash + '.' + tmpConfigFile)
+        var runtimePath = path.join(baseDir, 'bin', 'karma')
+
+        var executor = (done) => {
+          var cmd = runtimePath + ' ' + command + ' --log-level ' + level + ' ' + configFile + ' ' + additionalArgs
+
+          return exec(cmd, {
+            cwd: baseDir
+          }, done)
+        }
+
+        var runOut = command === 'runOut'
+        if (command === 'run' || command === 'runOut') {
+          this.child = spawn('' + runtimePath, ['start', '--log-level', 'warn', configFile])
+          var done = () => {
+            cleansingNeeded = true
+            this.child && this.child.kill()
+            callback()
+          }
+
+          this.child.on('error', (error) => {
+            this.lastRun.error = error
+            done()
+          })
+
+          this.child.stderr.on('data', (chunk) => {
+            this.lastRun.stderr += chunk.toString()
+          })
+
+          this.child.stdout.on('data', (chunk) => {
+            this.lastRun.stdout += chunk.toString()
+            var cmd = runtimePath + ' run ' + configFile + ' ' + additionalArgs
+            setTimeout(() => {
+              exec(cmd, {
+                cwd: baseDir
+              }, (error, stdout) => {
+                if (error) {
+                  this.lastRun.error = error
+                }
+                if (runOut) {
+                  this.lastRun.stdout = stdout
+                }
+                done()
+              })
+            }, 1000)
+          })
+        } else {
+          executor((error, stdout, stderr) => {
+            if (error) {
+              this.lastRun.error = error
+            }
+            this.lastRun.stdout = stdout
+            this.lastRun.stderr = stderr
+            cleansingNeeded = true
+            callback()
+          })
+        }
+      })
+    })
+  }
+
   Given('a configuration with:', function (fileContent, callback) {
     cleanseIfNeeded()
     this.addConfigContent(fileContent)
     return callback()
   })
 
-  Given('command line arguments of: {stringInDoubleQuotes}', function (args, callback) {
+  Given('command line arguments of: {string}', function (args, callback) {
     additionalArgs = args
     return callback()
   })
@@ -70,86 +155,34 @@ defineSupportCode(function ({defineParameterType, Given, Then, When}) {
     })(this))
   })
 
-  When("I {run|runOut|start|init|stop} Karma( with log-level {string})( behind a proxy on port {int} that prepends '{string}' to the base path)", function (command, level, proxyPort, proxyPath, callback) {
-    var startProxy = function (done) {
-      if (proxyPort) {
-        this.proxy.start(proxyPort, proxyPath, done)
-      } else {
-        done()
-      }
-    }
-    startProxy.call(this, (function (_this) {
-      return function (err) {
-        if (err) {
-          return callback.fail(err)
-        }
-        _this.writeConfigFile(tmpDir, tmpConfigFile, function (err, hash) {
-          if (err) {
-            return callback.fail(new Error(err))
-          }
-          level = level || 'warn'
-          var configFile = path.join(tmpDir, hash + '.' + tmpConfigFile)
-          var runtimePath = path.join(baseDir, 'bin', 'karma')
-          var execKarma = function (done) {
-            var cmd = runtimePath + ' ' + command + ' --log-level ' + level + ' ' + configFile + ' ' + additionalArgs
-
-            return exec(cmd, {
-              cwd: baseDir
-            }, done)
-          }
-          var runOut = command === 'runOut'
-          if (command === 'run' || command === 'runOut') {
-            _this.child = spawn('' + runtimePath, ['start', '--log-level', 'warn', configFile])
-            var done = function () {
-              cleansingNeeded = true
-              _this.child && _this.child.kill()
-              callback()
-            }
+  defineParameterType({
+    name: 'command',
+    regexp: /run|runOut|start|init|stop/
+  })
 
-            _this.child.on('error', function (error) {
-              _this.lastRun.error = error
-              done()
-            })
-
-            _this.child.stderr.on('data', function (chunk) {
-              _this.lastRun.stderr += chunk.toString()
-            })
-
-            _this.child.stdout.on('data', function (chunk) {
-              _this.lastRun.stdout += chunk.toString()
-              var cmd = runtimePath + ' run ' + configFile + ' ' + additionalArgs
-
-              setTimeout(function () {
-                exec(cmd, {
-                  cwd: baseDir
-                }, function (error, stdout) {
-                  if (error) {
-                    _this.lastRun.error = error
-                  }
-                  if (runOut) {
-                    _this.lastRun.stdout = stdout
-                  }
-                  done()
-                })
-              }, 1000)
-            })
-          } else {
-            execKarma(function (error, stdout, stderr) {
-              if (error) {
-                _this.lastRun.error = error
-              }
-              _this.lastRun.stdout = stdout
-              _this.lastRun.stderr = stderr
-              cleansingNeeded = true
-              callback()
-            })
-          }
-        })
-      }
-    })(this))
+  defineParameterType({
+    name: 'loglevel',
+    regexp: /info|error|warn|debug/
+  })
+
+  When('I {command} Karma', function (command, callback) {
+    execKarma.apply(this, [command, undefined, undefined, undefined, callback])
+  })
+
+  When('I {command} Karma with log-level {loglevel}', function (command, level, callback) {
+    execKarma.apply(this, [command, level, undefined, undefined, callback])
   })
 
-  Then('it passes with( {no debug|like}):', {timeout: 10 * 1000}, function (mode, expectedOutput, callback) {
+  When('I {command} Karma behind a proxy on port {int} that prepends {string} to the base path', function (command, proxyPort, proxyPath, callback) {
+    execKarma.apply(this, [command, undefined, proxyPort, proxyPath, callback])
+  })
+
+  defineParameterType({
+    name: 'exact',
+    regexp: /no\sdebug|like/
+  })
+
+  Then('it passes with( {exact}):', {timeout: 10 * 1000}, function (mode, expectedOutput, callback) {
     var noDebug = mode === 'no debug'
     var like = mode === 'like'
     var actualOutput = this.lastRun.stdout.toString()
@@ -203,7 +236,12 @@ defineSupportCode(function ({defineParameterType, Given, Then, When}) {
     }
   })
 
-  Then('The {server|stopper} is dead( with exit code {int})',
+  defineParameterType({
+    name: 'component',
+    regexp: /server|stopper/
+  })
+
+  Then('The {component} is dead( with exit code {int})',
     function (stopperOrServer, code, callback) {
       var server = stopperOrServer === 'server'
       var _this = this
@@ -215,7 +253,7 @@ defineSupportCode(function ({defineParameterType, Given, Then, When}) {
       }, 4000)
     })
 
-  Then('the file at {string} contains:',
+  Then(/^the file at ([a-zA-Z0-9/\\_.]+) contains:$/,
     function (filePath, expectedOutput, callback) {
       var data = fs.readFileSync(filePath, {encoding: 'UTF-8'})
       if (data.match(expectedOutput)) {
diff --git a/test/e2e/step_definitions/hooks.js b/test/e2e/step_definitions/hooks.js
index 9be4aa5ce..48e0e30ad 100644
--- a/test/e2e/step_definitions/hooks.js
+++ b/test/e2e/step_definitions/hooks.js
@@ -1,7 +1,7 @@
-var {defineSupportCode} = require('cucumber')
+var cucumber = require('cucumber')
 
-defineSupportCode(function ({After}) {
-  After(function (scenario, callback) {
+cucumber.defineSupportCode((a) => {
+  a.After(function (scenario, callback) {
     var running = this.child != null && typeof this.child.kill === 'function'
 
     if (running) {
diff --git a/test/e2e/support/env.js b/test/e2e/support/env.js
index e58cd18c9..566e5e7cb 100644
--- a/test/e2e/support/env.js
+++ b/test/e2e/support/env.js
@@ -1,5 +1,5 @@
-var {defineSupportCode} = require('cucumber')
+var cucumber = require('cucumber')
 
-defineSupportCode(function ({setDefaultTimeout}) {
-  setDefaultTimeout(60 * 1000)
+cucumber.defineSupportCode((a) => {
+  a.setDefaultTimeout(60 * 1000)
 })
diff --git a/test/e2e/support/world.js b/test/e2e/support/world.js
index 584b3bbd7..69d28c185 100644
--- a/test/e2e/support/world.js
+++ b/test/e2e/support/world.js
@@ -4,7 +4,7 @@ var path = require('path')
 var hasher = require('crypto').createHash
 var mkdirp = require('mkdirp')
 var _ = require('lodash')
-var {defineSupportCode} = require('cucumber')
+var cucumber = require('cucumber')
 
 function World () {
   this.proxy = require('./proxy')
@@ -63,6 +63,6 @@ function World () {
   }
 }
 
-defineSupportCode(function ({setWorldConstructor}) {
-  setWorldConstructor(World)
+cucumber.defineSupportCode((a) => {
+  a.setWorldConstructor(World)
 })
diff --git a/test/unit/cli.spec.js b/test/unit/cli.spec.js
index a48707776..04744d96d 100644
--- a/test/unit/cli.spec.js
+++ b/test/unit/cli.spec.js
@@ -1,8 +1,10 @@
-import cli from '../../lib/cli'
-import optimist from 'optimist'
-import path from 'path'
-import constant from '../../lib/constants'
-import mocks from 'mocks'
+var optimist = require('optimist')
+var path = require('path')
+var mocks = require('mocks')
+
+var cli = require('../../lib/cli')
+var constant = require('../../lib/constants')
+
 var loadFile = mocks.loadFile
 
 describe('cli', () => {
diff --git a/test/unit/config.spec.js b/test/unit/config.spec.js
index f2c65a41b..f9cae34f8 100644
--- a/test/unit/config.spec.js
+++ b/test/unit/config.spec.js
@@ -1,4 +1,4 @@
-import path from 'path'
+var path = require('path')
 var loadFile = require('mocks').loadFile
 var helper = require('../../lib/helper')
 var logger = require('../../lib/logger.js')
@@ -123,10 +123,8 @@ describe('config', () => {
 
       expect(logSpy).to.have.been.called
       var event = logSpy.lastCall.args
-      expect(event).to.be.deep.equal([
-        'Error in config file!\n',
-        new SyntaxError('Unexpected token =')
-      ])
+      expect(event[0]).to.eql('Error in config file!\n')
+      expect(event[1].message).to.eql('Unexpected token =')
       expect(mocks.process.exit).to.have.been.calledWith(1)
     })
 
@@ -423,7 +421,9 @@ describe('config', () => {
   describe('custom', () => {
     var di = require('di')
 
-    var forwardArgsFactory = (args) => args
+    var forwardArgsFactory = function (args) {
+      return args
+    }
 
     var baseModule = {
       'preprocessor:base': ['type', forwardArgsFactory],
@@ -445,7 +445,7 @@ describe('config', () => {
       var injector = new di.Injector([baseModule].concat(config.plugins))
       var injectedArgs = injector.get('launcher:custom')
 
-      expect(injectedArgs).to.be.defined
+      expect(injectedArgs).to.exist
       expect(injectedArgs.first).to.equal(123)
       expect(injectedArgs.whatever).to.equal('aaa')
     })
@@ -464,7 +464,7 @@ describe('config', () => {
       var injector = new di.Injector([baseModule].concat(config.plugins))
       var injectedArgs = injector.get('preprocessor:custom')
 
-      expect(injectedArgs).to.be.defined
+      expect(injectedArgs).to.exist
       expect(injectedArgs.second).to.equal(123)
       expect(injectedArgs.whatever).to.equal('bbb')
     })
@@ -483,7 +483,7 @@ describe('config', () => {
       var injector = new di.Injector([baseModule].concat(config.plugins))
       var injectedArgs = injector.get('reporter:custom')
 
-      expect(injectedArgs).to.be.defined
+      expect(injectedArgs).to.exist
       expect(injectedArgs.third).to.equal(123)
       expect(injectedArgs.whatever).to.equal('ccc')
     })
diff --git a/test/unit/emitter_wrapper.spec.js b/test/unit/emitter_wrapper.spec.js
index 1692ebac8..d8aecce8c 100644
--- a/test/unit/emitter_wrapper.spec.js
+++ b/test/unit/emitter_wrapper.spec.js
@@ -1,5 +1,6 @@
-import EmitterWrapper from '../../lib/emitter_wrapper'
-import {EventEmitter} from 'events'
+var EventEmitter = require('events').EventEmitter
+
+var EmitterWrapper = require('../../lib/emitter_wrapper')
 
 describe('emitter_wrapper', () => {
   var emitter
diff --git a/test/unit/events.spec.js b/test/unit/events.spec.js
index e058e7b57..cf35f345a 100644
--- a/test/unit/events.spec.js
+++ b/test/unit/events.spec.js
@@ -147,7 +147,7 @@ describe('events', () => {
       emitter.on('bar', spy)
 
       replyEvents()
-      expect(spy).to.not.have.been.caleed
+      expect(spy).to.not.have.been.called
     })
 
     it('should work with overriden "emit" method', () => {
diff --git a/test/unit/file-list.spec.js b/test/unit/file-list.spec.js
index 97b1b90b6..9a6ad1af0 100644
--- a/test/unit/file-list.spec.js
+++ b/test/unit/file-list.spec.js
@@ -1,23 +1,24 @@
-import Promise from 'bluebird'
-import {EventEmitter} from 'events'
-import mocks from 'mocks'
-import proxyquire from 'proxyquire'
-import pathLib from 'path'
-import _ from 'lodash'
-import from from 'core-js/library/fn/array/from'
+var Promise = require('bluebird')
+var EventEmitter = require('events').EventEmitter
+var mocks = require('mocks')
+var proxyquire = require('proxyquire')
+var pathLib = require('path')
+var _ = require('lodash')
 
-import helper from '../../lib/helper'
-import config from '../../lib/config'
+var helper = require('../../lib/helper')
+var config = require('../../lib/config')
 
 // create an array of pattern objects from given strings
-var patterns = (...strings) => strings.map((str) => new config.Pattern(str))
+var patterns = function () {
+  return Array.from(arguments).map((str) => new config.Pattern(str))
+}
 
 function pathsFrom (files) {
-  return _.map(from(files), 'path')
+  return _.map(Array.from(files), 'path')
 }
 
 function findFile (path, files) {
-  return from(files).find((file) => file.path === path)
+  return Array.from(files).find((file) => file.path === path)
 }
 
 var PATTERN_LIST = {
@@ -71,10 +72,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       List = proxyquire('../../lib/file-list', {
@@ -104,7 +107,7 @@ describe('FileList', () => {
 
     it('returns only served files', () => {
       var files = [
-        new config.Pattern('/a.*', true),        // served: true
+        new config.Pattern('/a.*', true), // served: true
         new config.Pattern('/some/*.js', false) // served: false
       ]
 
@@ -117,7 +120,7 @@ describe('FileList', () => {
 
     it('marks no cache files', () => {
       var files = [
-        new config.Pattern('/a.*'),        // nocach: false
+        new config.Pattern('/a.*'), // nocach: false
         new config.Pattern('/some/*.js', true, true, true, true) // nocache: true
       ]
 
@@ -201,10 +204,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       List = proxyquire('../../lib/file-list', {
@@ -238,10 +243,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       List = proxyquire('../../lib/file-list', {
@@ -363,8 +370,7 @@ describe('FileList', () => {
           var file = findFile('http://some.com', bucket)
 
           expect(file).to.have.property('isUrl', true)
-        }
-      )
+        })
     })
 
     it('preprocesses all files', () => {
@@ -416,8 +422,7 @@ describe('FileList', () => {
       ])
         .then(() => {
           expect(list._refresh).to.have.been.calledTwice
-        }
-      )
+        })
     })
   })
 
@@ -432,10 +437,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       clock = sinon.useFakeTimers()
@@ -559,10 +566,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       clock = sinon.useFakeTimers()
@@ -666,10 +675,12 @@ describe('FileList', () => {
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       clock = sinon.useFakeTimers()
@@ -741,16 +752,18 @@ describe('FileList', () => {
     beforeEach(() => {
       patternList = PATTERN_LIST
       mg = MG
-      Promise.setScheduler((fn) => fn())
+      Promise.setScheduler(function (fn) { fn() })
 
       preprocess = sinon.spy((file, done) => process.nextTick(done))
       emitter = new EventEmitter()
 
       glob = {
-        Glob: (pattern, opts) => ({
-          found: patternList[pattern],
-          statCache: mg.statCache
-        })
+        Glob: function (pattern, opts) {
+          return {
+            found: patternList[pattern],
+            statCache: mg.statCache
+          }
+        }
       }
 
       modified = sinon.stub()
@@ -873,9 +886,10 @@ describe('FileList', () => {
         mockFs._touchFile('/some/b.js', '2020-01-01')
         list.changeFile('/some/b.js')
         list.removeFile('/some/a.js') // /some/b.js, /a.txt
-        list.removeFile('/a.txt')     // /some/b.js
-        list.addFile('/a.txt')        // /some/b.js, /a.txt
-        list.addFile('/some/0.js').then(() => {     // /some/0.js, /some/b.js, /a.txt
+        list.removeFile('/a.txt') // /some/b.js
+        list.addFile('/a.txt') // /some/b.js, /a.txt
+        list.addFile('/some/0.js').then(() => {
+          // /some/0.js, /some/b.js, /a.txt
           clock.tick(99)
           expect(modified).to.not.have.been.called
           mockFs._touchFile('/a.txt', '2020-01-01')
diff --git a/test/unit/helper.spec.js b/test/unit/helper.spec.js
index 118e7e9b3..c937bb95d 100644
--- a/test/unit/helper.spec.js
+++ b/test/unit/helper.spec.js
@@ -1,4 +1,4 @@
-import path from 'path'
+var path = require('path')
 
 describe('helper', () => {
   var helper = require('../../lib/helper')
diff --git a/test/unit/init.spec.js b/test/unit/init.spec.js
index d38884b24..3bcdd0ef6 100644
--- a/test/unit/init.spec.js
+++ b/test/unit/init.spec.js
@@ -1,4 +1,5 @@
-import path from 'path'
+var path = require('path')
+
 describe('init', () => {
   var loadFile = require('mocks').loadFile
   var m = null
diff --git a/test/unit/init/formatters.spec.js b/test/unit/init/formatters.spec.js
index a311132f6..3a46667ca 100644
--- a/test/unit/init/formatters.spec.js
+++ b/test/unit/init/formatters.spec.js
@@ -1,4 +1,5 @@
-import formatters from '../../../lib/init/formatters'
+var formatters = require('../../../lib/init/formatters')
+
 describe('init/formatters', () => {
   var formatter
 
@@ -8,7 +9,8 @@ describe('init/formatters', () => {
     })
 
     describe('formatAnswers', () => {
-      var createAnswers = function (ans = {}) {
+      var createAnswers = function (ans) {
+        ans = ans || {}
         ans.frameworks = ans.frameworks || []
         ans.files = ans.files || []
         ans.onlyServedFiles = ans.onlyServedFiles || []
diff --git a/test/unit/init/state_machine.spec.js b/test/unit/init/state_machine.spec.js
index f2ab7ad0e..5bd620211 100644
--- a/test/unit/init/state_machine.spec.js
+++ b/test/unit/init/state_machine.spec.js
@@ -1,4 +1,4 @@
-import StateMachine from '../../../lib/init/state_machine'
+var StateMachine = require('../../../lib/init/state_machine')
 
 describe('init/StateMachine', () => {
   var done
diff --git a/test/unit/launcher.spec.js b/test/unit/launcher.spec.js
index aa3662599..8b69955d5 100644
--- a/test/unit/launcher.spec.js
+++ b/test/unit/launcher.spec.js
@@ -1,8 +1,9 @@
-import Promise from 'bluebird'
-import di from 'di'
-import events from '../../lib/events'
-import launcher from '../../lib/launcher'
-import createMockTimer from './mocks/timer'
+var Promise = require('bluebird')
+var di = require('di')
+
+var events = require('../../lib/events')
+var launcher = require('../../lib/launcher')
+var createMockTimer = require('./mocks/timer')
 
 // promise mock
 var stubPromise = (obj, method, stubAction) => {
@@ -17,48 +18,44 @@ var stubPromise = (obj, method, stubAction) => {
   })
 }
 
-class FakeBrowser {
-  constructor (id, name, baseBrowserDecorator) {
-    this.id = id
-    this.name = name
-    this.DEFAULT_CMD = {
-      linux: '/script',
-      darwin: '/script',
-      win32: 'script.exe'
-    }
-    this.ENV_CMD = 'SCRIPT_BIN'
-
-    baseBrowserDecorator(this)
-    FakeBrowser._instances.push(this)
-    sinon.stub(this, 'start').callsFake(() => {
-      this.state = this.STATE_BEING_CAPTURED
-      this._done()
-    })
-    stubPromise(this, 'forceKill')
-    sinon.stub(this, 'restart')
+function FakeBrowser (id, name, baseBrowserDecorator) {
+  this.id = id
+  this.name = name
+  this.DEFAULT_CMD = {
+    linux: '/script',
+    darwin: '/script',
+    win32: 'script.exe'
   }
+  this.ENV_CMD = 'SCRIPT_BIN'
+
+  baseBrowserDecorator(this)
+  FakeBrowser._instances.push(this)
+  sinon.stub(this, 'start').callsFake(() => {
+    this.state = this.STATE_BEING_CAPTURED
+    this._done()
+  })
+  stubPromise(this, 'forceKill')
+  sinon.stub(this, 'restart')
 }
 
-class ScriptBrowser {
-  constructor (id, name, baseBrowserDecorator) {
-    this.id = id
-    this.name = name
-    this.DEFAULT_CMD = {
-      linux: '/script',
-      darwin: '/script',
-      win32: 'script.exe'
-    }
-    this.ENV_CMD = 'SCRIPT_BIN'
-
-    baseBrowserDecorator(this)
-    ScriptBrowser._instances.push(this)
-    sinon.stub(this, 'start').callsFake(() => {
-      this.state = this.STATE_BEING_CAPTURED
-      this._done()
-    })
-    stubPromise(this, 'forceKill')
-    sinon.stub(this, 'restart')
+function ScriptBrowser (id, name, baseBrowserDecorator) {
+  this.id = id
+  this.name = name
+  this.DEFAULT_CMD = {
+    linux: '/script',
+    darwin: '/script',
+    win32: 'script.exe'
   }
+  this.ENV_CMD = 'SCRIPT_BIN'
+
+  baseBrowserDecorator(this)
+  ScriptBrowser._instances.push(this)
+  sinon.stub(this, 'start').callsFake(() => {
+    this.state = this.STATE_BEING_CAPTURED
+    this._done()
+  })
+  stubPromise(this, 'forceKill')
+  sinon.stub(this, 'restart')
 }
 
 describe('launcher', () => {
diff --git a/test/unit/launchers/base.spec.js b/test/unit/launchers/base.spec.js
index 8357770dc..89408defd 100644
--- a/test/unit/launchers/base.spec.js
+++ b/test/unit/launchers/base.spec.js
@@ -1,7 +1,7 @@
-import _ from 'lodash'
+var _ = require('lodash')
 
-import BaseLauncher from '../../../lib/launchers/base'
-import {EventEmitter} from '../../../lib/events'
+var BaseLauncher = require('../../../lib/launchers/base')
+var EventEmitter = require('../../../lib/events').EventEmitter
 
 describe('launchers/base.js', () => {
   var emitter
diff --git a/test/unit/launchers/capture_timeout.spec.js b/test/unit/launchers/capture_timeout.spec.js
index 636dfee1d..46e62debc 100644
--- a/test/unit/launchers/capture_timeout.spec.js
+++ b/test/unit/launchers/capture_timeout.spec.js
@@ -1,6 +1,6 @@
-import BaseLauncher from '../../../lib/launchers/base'
-import CaptureTimeoutLauncher from '../../../lib/launchers/capture_timeout'
-import createMockTimer from '../mocks/timer'
+var BaseLauncher = require('../../../lib/launchers/base')
+var CaptureTimeoutLauncher = require('../../../lib/launchers/capture_timeout')
+var createMockTimer = require('../mocks/timer')
 
 describe('launchers/capture_timeout.js', () => {
   var timer
diff --git a/test/unit/launchers/process.spec.js b/test/unit/launchers/process.spec.js
index f97c28907..746747007 100644
--- a/test/unit/launchers/process.spec.js
+++ b/test/unit/launchers/process.spec.js
@@ -1,12 +1,12 @@
-import path from 'path'
-import _ from 'lodash'
-
-import BaseLauncher from '../../../lib/launchers/base'
-import RetryLauncher from '../../../lib/launchers/retry'
-import CaptureTimeoutLauncher from '../../../lib/launchers/capture_timeout'
-import ProcessLauncher from '../../../lib/launchers/process'
-import {EventEmitter} from '../../../lib/events'
-import createMockTimer from '../mocks/timer'
+var path = require('path')
+var _ = require('lodash')
+
+var BaseLauncher = require('../../../lib/launchers/base')
+var RetryLauncher = require('../../../lib/launchers/retry')
+var CaptureTimeoutLauncher = require('../../../lib/launchers/capture_timeout')
+var ProcessLauncher = require('../../../lib/launchers/process')
+var EventEmitter = require('../../../lib/events').EventEmitter
+var createMockTimer = require('../mocks/timer')
 
 describe('launchers/process.js', () => {
   var emitter
diff --git a/test/unit/launchers/retry.spec.js b/test/unit/launchers/retry.spec.js
index 4129ec5b9..90bd69579 100644
--- a/test/unit/launchers/retry.spec.js
+++ b/test/unit/launchers/retry.spec.js
@@ -1,8 +1,8 @@
-import _ from 'lodash'
+var _ = require('lodash')
 
-import BaseLauncher from '../../../lib/launchers/base'
-import RetryLauncher from '../../../lib/launchers/retry'
-import {EventEmitter} from '../../../lib/events'
+var BaseLauncher = require('../../../lib/launchers/base')
+var RetryLauncher = require('../../../lib/launchers/retry')
+var EventEmitter = require('../../../lib/events').EventEmitter
 
 describe('launchers/retry.js', () => {
   var emitter
diff --git a/test/unit/logger.spec.js b/test/unit/logger.spec.js
index 917aa82ab..d3ea57fcd 100644
--- a/test/unit/logger.spec.js
+++ b/test/unit/logger.spec.js
@@ -1,12 +1,12 @@
-import {loadFile} from 'mocks'
-import path from 'path'
+var loadFile = require('mocks').loadFile
+var path = require('path')
 
 describe('logger', () => {
   var m
-  let configuration
+  var configuration
 
   beforeEach(() => {
-    const mockLog4Js = {
+    var mockLog4Js = {
       configure: function (config) {
         configuration = config
       }
diff --git a/test/unit/middleware/karma.spec.js b/test/unit/middleware/karma.spec.js
index 9804da6a0..633a92152 100644
--- a/test/unit/middleware/karma.spec.js
+++ b/test/unit/middleware/karma.spec.js
@@ -1,8 +1,9 @@
-import helper from '../../../lib/helper'
-import constants from '../../../lib/constants'
-import File from '../../../lib/file'
-import Url from '../../../lib/url'
-import mocks from 'mocks'
+var mocks = require('mocks')
+
+var helper = require('../../../lib/helper')
+var constants = require('../../../lib/constants')
+var File = require('../../../lib/file')
+var Url = require('../../../lib/url')
 
 var HttpResponseMock = mocks.http.ServerResponse
 var HttpRequestMock = mocks.http.ServerRequest
@@ -415,7 +416,7 @@ describe('middleware.karma', () => {
   })
 
   it('should update handle updated configs', (done) => {
-    let i = 0
+    var i = 0
     handler = createKarmaMiddleware(
       filesDeferred.promise,
       serveFile,
diff --git a/test/unit/middleware/proxy.spec.js b/test/unit/middleware/proxy.spec.js
index 9b81a27c8..73bb0f9f9 100644
--- a/test/unit/middleware/proxy.spec.js
+++ b/test/unit/middleware/proxy.spec.js
@@ -1,4 +1,4 @@
-import path from 'path'
+var path = require('path')
 var httpMock = require('mocks').http
 var loadFile = require('mocks').loadFile
 
diff --git a/test/unit/middleware/runner.spec.js b/test/unit/middleware/runner.spec.js
index e773f1c26..9a7985fb3 100644
--- a/test/unit/middleware/runner.spec.js
+++ b/test/unit/middleware/runner.spec.js
@@ -1,12 +1,14 @@
-import path from 'path'
-import {EventEmitter} from 'events'
-import mocks from 'mocks'
-import {Promise} from 'bluebird'
-import Browser from '../../../lib/browser'
-import BrowserCollection from '../../../lib/browser_collection'
-import MultReporter from '../../../lib/reporters/multi'
+var path = require('path')
+var EventEmitter = require('events').EventEmitter
+var mocks = require('mocks')
+var Promise = require('bluebird')
 var _ = require('lodash')
+
+var Browser = require('../../../lib/browser')
+var BrowserCollection = require('../../../lib/browser_collection')
+var MultReporter = require('../../../lib/reporters/multi')
 var createRunnerMiddleware = require('../../../lib/middleware/runner').create
+
 var HttpResponseMock = mocks.http.ServerResponse
 var HttpRequestMock = mocks.http.ServerRequest
 
diff --git a/test/unit/middleware/source_files.spec.js b/test/unit/middleware/source_files.spec.js
index 9b3bc3c2f..92475d373 100644
--- a/test/unit/middleware/source_files.spec.js
+++ b/test/unit/middleware/source_files.spec.js
@@ -1,9 +1,10 @@
-import http from 'http'
-import mocks from 'mocks'
-import request from 'supertest'
-import helper from '../../../lib/helper'
-import File from '../../../lib/file'
-import {createServeFile} from '../../../lib/middleware/common'
+var http = require('http')
+var mocks = require('mocks')
+var request = require('supertest')
+
+var helper = require('../../../lib/helper')
+var File = require('../../../lib/file')
+var createServeFile = require('../../../lib/middleware/common').createServeFile
 var createSourceFilesMiddleware = require('../../../lib/middleware/source_files').create
 
 describe('middleware.source_files', function () {
@@ -128,8 +129,7 @@ describe('middleware.source_files', function () {
       .expect(200, 'js-src-a')
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   it('should send strict caching headers for js source files with sha', function () {
@@ -143,8 +143,7 @@ describe('middleware.source_files', function () {
       .expect(200)
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   it('should send strict caching headers for js source files with sha (in basePath)', function () {
@@ -174,8 +173,7 @@ describe('middleware.source_files', function () {
       .expect(200)
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   it('should not serve files that are not in served', function () {
@@ -208,8 +206,7 @@ describe('middleware.source_files', function () {
       .expect(200, 'utf8-file')
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   it('should serve js source file from paths containing HTML URL encoded chars', function () {
@@ -224,8 +221,7 @@ describe('middleware.source_files', function () {
       .expect(200, 'utf8-file')
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   it('should set content-type headers', function () {
@@ -252,8 +248,7 @@ describe('middleware.source_files', function () {
       .expect(200, 'cached-content')
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 
   return it('should not use cached content if doNotCache is set', function () {
@@ -270,7 +265,6 @@ describe('middleware.source_files', function () {
       .expect(200, 'js-source')
       .then(function () {
         return expect(next).not.to.have.been.called
-      }
-    )
+      })
   })
 })
diff --git a/test/unit/middleware/strip_host.spec.js b/test/unit/middleware/strip_host.spec.js
index 39681533a..5983e61c8 100644
--- a/test/unit/middleware/strip_host.spec.js
+++ b/test/unit/middleware/strip_host.spec.js
@@ -1,4 +1,4 @@
-import mocks from 'mocks'
+var mocks = require('mocks')
 
 describe('middleware.strip_host', function () {
   var nextSpy
diff --git a/test/unit/mocks/timer.js b/test/unit/mocks/timer.js
index 943201fd3..8abb35e9b 100644
--- a/test/unit/mocks/timer.js
+++ b/test/unit/mocks/timer.js
@@ -1,4 +1,4 @@
-import {Timer} from 'timer-shim'
+var Timer = require('timer-shim').Timer
 
 module.exports = function () {
   var timer = new Timer()
diff --git a/test/unit/preprocessor.spec.js b/test/unit/preprocessor.spec.js
index ccd488f3a..cddca6c68 100644
--- a/test/unit/preprocessor.spec.js
+++ b/test/unit/preprocessor.spec.js
@@ -1,7 +1,8 @@
-import mocks from 'mocks'
-import di from 'di'
-import path from 'path'
-import events from '../../lib/events'
+var mocks = require('mocks')
+var di = require('di')
+var path = require('path')
+
+var events = require('../../lib/events')
 
 describe('preprocessor', () => {
   var pp
@@ -39,7 +40,11 @@ describe('preprocessor', () => {
       done(null, 'new-content')
     })
 
-    var injector = new di.Injector([{'preprocessor:fake': ['factory', () => fakePreprocessor]}, emitterSetting])
+    var injector = new di.Injector([{
+      'preprocessor:fake': [
+        'factory', function () { return fakePreprocessor }
+      ]
+    }, emitterSetting])
     pp = m.createPreprocessor({'**/*.js': ['fake']}, null, injector)
 
     var file = {originalPath: '/some/a.js', path: 'path'}
@@ -58,7 +63,9 @@ describe('preprocessor', () => {
       done(null, 'new-content')
     })
 
-    var injector = new di.Injector([{'preprocessor:fake': ['factory', () => fakePreprocessor]}, emitterSetting])
+    var injector = new di.Injector([{
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor } ]
+    }, emitterSetting])
     pp = m.createPreprocessor({'**/*.js': ['fake']}, null, injector)
 
     var file = {originalPath: '/some/.dir/a.js', path: 'path'}
@@ -77,7 +84,9 @@ describe('preprocessor', () => {
       done(null, 'new-content')
     })
 
-    var injector = new di.Injector([{'preprocessor:fake': ['factory', () => fakePreprocessor]}, emitterSetting])
+    var injector = new di.Injector([{
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
+    }, emitterSetting])
     var config = {'**/*.txt': ['fake']}
     pp = m.createPreprocessor(config, null, injector)
 
@@ -98,7 +107,9 @@ describe('preprocessor', () => {
       done(null, '')
     })
 
-    var injector = new di.Injector([{'preprocessor:fake': ['factory', () => fakePreprocessor]}, emitterSetting])
+    var injector = new di.Injector([{
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
+    }, emitterSetting])
     pp = m.createPreprocessor({'**/*.js': ['fake']}, null, injector)
 
     var file = {originalPath: '/some/a.txt', path: 'path'}
@@ -121,8 +132,8 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:fake1': ['factory', () => fakePreprocessor1],
-      'preprocessor:fake2': ['factory', () => fakePreprocessor2]
+      'preprocessor:fake1': ['factory', function () { return fakePreprocessor1 }],
+      'preprocessor:fake2': ['factory', function () { return fakePreprocessor2 }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/*.js': ['fake1', 'fake2']}, null, injector)
@@ -166,7 +177,7 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:fake': ['factory', () => fakePreprocessor]
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/a.js': ['fake']}, null, injector)
@@ -192,7 +203,7 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:failing': ['factory', () => failingPreprocessor]
+      'preprocessor:failing': ['factory', function () { return failingPreprocessor }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/*.js': ['failing']}, null, injector)
@@ -215,8 +226,8 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:failing': ['factory', () => failingPreprocessor],
-      'preprocessor:fake': ['factory', () => fakePreprocessor]
+      'preprocessor:failing': ['factory', function () { return failingPreprocessor }],
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/*.js': ['failing', 'fake']}, null, injector)
@@ -245,7 +256,7 @@ describe('preprocessor', () => {
       })
 
       var injector = new di.Injector([{
-        'preprocessor:fake': ['factory', () => fakePreprocessor]
+        'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
       }, emitterSetting])
 
       var pp = m.createPreprocessor({'**/*.js': ['fake']}, null, injector)
@@ -283,7 +294,7 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:fake': ['factory', () => fakePreprocessor]
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/*': ['fake']}, null, injector)
@@ -305,7 +316,7 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:fake': ['factory', () => fakePreprocessor]
+      'preprocessor:fake': ['factory', function () { fakePreprocessor }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({'**/*': ['fake']}, null, injector)
@@ -341,10 +352,10 @@ describe('preprocessor', () => {
     })
 
     var injector = new di.Injector([{
-      'preprocessor:fakeA': ['factory', () => fakePreprocessorA],
-      'preprocessor:fakeB': ['factory', () => fakePreprocessorB],
-      'preprocessor:fakeC': ['factory', () => fakePreprocessorC],
-      'preprocessor:fakeD': ['factory', () => fakePreprocessorD]
+      'preprocessor:fakeA': ['factory', function () { return fakePreprocessorA }],
+      'preprocessor:fakeB': ['factory', function () { return fakePreprocessorB }],
+      'preprocessor:fakeC': ['factory', function () { return fakePreprocessorC }],
+      'preprocessor:fakeD': ['factory', function () { return fakePreprocessorD }]
     }, emitterSetting])
 
     pp = m.createPreprocessor({
diff --git a/test/unit/reporter.spec.js b/test/unit/reporter.spec.js
index af344856b..cb8dd15c3 100644
--- a/test/unit/reporter.spec.js
+++ b/test/unit/reporter.spec.js
@@ -1,10 +1,12 @@
-import {EventEmitter} from 'events'
-import {loadFile} from 'mocks'
-import path from 'path'
-import _ from 'lodash'
-import sinon from 'sinon'
+'use strict'
 
-import File from '../../lib/file'
+var EventEmitter = require('events').EventEmitter
+var loadFile = require('mocks').loadFile
+var path = require('path')
+var _ = require('lodash')
+var sinon = require('sinon')
+
+var File = require('../../lib/file')
 
 describe('reporter', () => {
   var m
diff --git a/test/unit/reporters/base.spec.js b/test/unit/reporters/base.spec.js
index ed75037ad..38efff419 100644
--- a/test/unit/reporters/base.spec.js
+++ b/test/unit/reporters/base.spec.js
@@ -1,4 +1,4 @@
-import path from 'path'
+var path = require('path')
 
 describe('reporter', function () {
   var loadFile = require('mocks').loadFile
diff --git a/test/unit/runner.spec.js b/test/unit/runner.spec.js
index 98fcb2118..064be9aea 100644
--- a/test/unit/runner.spec.js
+++ b/test/unit/runner.spec.js
@@ -1,6 +1,7 @@
-import {loadFile} from 'mocks'
-import constant from '../../lib/constants'
-import path from 'path'
+var loadFile = require('mocks').loadFile
+var path = require('path')
+
+var constant = require('../../lib/constants')
 
 describe('runner', () => {
   var m
diff --git a/test/unit/server.spec.js b/test/unit/server.spec.js
index 248ad1f4b..c362f1aed 100644
--- a/test/unit/server.spec.js
+++ b/test/unit/server.spec.js
@@ -1,5 +1,5 @@
-import Server from '../../lib/server'
-import BrowserCollection from '../../lib/browser_collection'
+var Server = require('../../lib/server')
+var BrowserCollection = require('../../lib/browser_collection')
 
 describe('server', () => {
   var mockConfig
diff --git a/test/unit/watcher.spec.js b/test/unit/watcher.spec.js
index fb07f8d7e..a3bec71bd 100644
--- a/test/unit/watcher.spec.js
+++ b/test/unit/watcher.spec.js
@@ -1,5 +1,5 @@
-import mocks from 'mocks'
-import path from 'path'
+var mocks = require('mocks')
+var path = require('path')
 
 describe('watcher', () => {
   var config = require('../../lib/config')
diff --git a/test/unit/web-server.spec.js b/test/unit/web-server.spec.js
index ca7e1401e..d429e443c 100644
--- a/test/unit/web-server.spec.js
+++ b/test/unit/web-server.spec.js
@@ -1,11 +1,10 @@
-import 'core-js'
-import {EventEmitter} from 'events'
-import request from 'supertest'
-import di from 'di'
-import mocks from 'mocks'
-import fs from 'fs'
-import mime from 'mime'
-import path from 'path'
+var EventEmitter = require('events').EventEmitter
+var request = require('supertest')
+var di = require('di')
+var mocks = require('mocks')
+var fs = require('fs')
+var mime = require('mime')
+var path = require('path')
 
 describe('web-server', () => {
   var server