diff --git a/cli.js b/cli.js
index f2e438a6..9b4e8329 100755
--- a/cli.js
+++ b/cli.js
@@ -1,5 +1,7 @@
 #!/usr/bin/env node
+
 'use strict';
+
 const os = require('os');
 const path = require('path');
 const chalk = require('chalk');
diff --git a/index.js b/index.js
index ea4d603e..6a19bd61 100644
--- a/index.js
+++ b/index.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const path = require('path');
 const fs = require('fs-extra');
 const assign = require('lodash/assign');
@@ -82,7 +83,7 @@ function prepareOptions(opts) {
  * @accepts src, base, width, height, dimensions, dest
  * @return {Promise}|undefined
  */
-exports.generate = function (opts, cb) {
+exports.generate = (opts, cb) => {
     opts = prepareOptions(opts);
 
     // Generate critical css
@@ -134,14 +135,14 @@ exports.generate = function (opts, cb) {
 /**
  * Deprecated has been removed
  */
-exports.generateInline = function () {
+exports.generateInline = () => {
     throw new Error('"generateInline" has been removed. Use "generate" with the inline option instead. https://goo.gl/7VbE4b');
 };
 
 /**
  * Deprecated has been removed
  */
-exports.inline = function () {
+exports.inline = () => {
     throw new Error('"inline" has been removed. Consider using "inline-critical" instead. https://goo.gl/MmTrUZ');
 };
 
@@ -151,7 +152,7 @@ exports.inline = function () {
  * @param {object} opts
  * @returns {*}
  */
-exports.stream = function (opts) {
+exports.stream = opts => {
     // Return stream
     return through2.obj(function (file, enc, cb) {
         if (file.isNull()) {
diff --git a/lib/core.js b/lib/core.js
index 0956638d..12a2810a 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const os = require('os');
 const path = require('path');
 const url = require('url');
@@ -52,7 +53,7 @@ function combineCss(cssArray) {
  * @returns {function}
  */
 function appendStylesheets(opts) {
-    return function (htmlfile) {
+    return htmlfile => {
         // Consider opts.css and map to array if it isn't one
         if (opts.css) {
             const css = Array.isArray(opts.css) ? opts.css : [opts.css];
@@ -88,7 +89,7 @@ function appendStylesheets(opts) {
  * @returns {function}
  */
 function inlineImages(opts) {
-    return function (vinyl) {
+    return vinyl => {
         if (opts.inlineImages) {
             const assetPaths = opts.assetPaths || [];
 
@@ -100,7 +101,7 @@ function inlineImages(opts) {
                 if (file.isExternal(opts.src)) {
                     // eslint-disable-next-line node/no-deprecated-api
                     const urlObj = url.parse(opts.src);
-                    const domain = urlObj.protocol + '//' + urlObj.host;
+                    const domain = `${urlObj.protocol}//${urlObj.host}`;
                     assetPaths.push(domain, domain + path.dirname(urlObj.pathname));
                 }
 
@@ -132,7 +133,7 @@ function inlineImages(opts) {
  * @returns {function}
  */
 function vinylize(opts) {
-    return function (filepath) {
+    return filepath => {
         if (filepath._isVinyl) {
             return filepath;
         }
@@ -151,7 +152,7 @@ function vinylize(opts) {
  * @returns {function}
  */
 function processStylesheets(opts) {
-    return function (htmlfile) {
+    return htmlfile => {
         debug('processStylesheets', htmlfile.stylesheets);
         return Bluebird.map(htmlfile.stylesheets, vinylize(opts))
             .map(inlineImages(opts))
@@ -174,8 +175,8 @@ function processStylesheets(opts) {
  * @returns {function}
  */
 function computeCritical(dimensions, opts) {
-    return function (htmlfile) {
-        debug('Processing: ' + htmlfile.path + ' [' + dimensions.width + 'x' + dimensions.height + ']');
+    return htmlfile => {
+        debug(`Processing: ${htmlfile.path} [${dimensions.width}x${dimensions.height}]`);
         const penthouseOpts = assign({}, opts.penthouse, {
             url: file.getPenthouseUrl(opts, htmlfile),
             cssString: htmlfile.cssString,
@@ -185,7 +186,7 @@ function computeCritical(dimensions, opts) {
         });
 
         if (opts.user && opts.pass) {
-            penthouseOpts.customPageHeaders = {Authorization: 'Basic ' + file.token(opts.user, opts.pass)};
+            penthouseOpts.customPageHeaders = {Authorization: `Basic ${file.token(opts.user, opts.pass)}`};
         }
 
         return penthouse(penthouseOpts);
diff --git a/lib/file-helper.js b/lib/file-helper.js
index 9c70d4b3..0e9f710e 100644
--- a/lib/file-helper.js
+++ b/lib/file-helper.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const os = require('os');
 const url = require('url');
 const path = require('path');
@@ -41,7 +42,7 @@ function replaceAssetPaths(html, opts) {
     /**
      * The resulting function should get passed an vinyl object with the css file
      */
-    return function (stylesheet) {
+    return stylesheet => {
         // Normalize relative paths
         const css = stylesheet.contents.toString().replace(/url\(['"]?([^'"\\)]+)['"]?\)/g, (match, assetPath) => {
             // Skip absolute paths, urls and data-uris
@@ -84,8 +85,8 @@ function getPenthouseUrl(opts, file) {
         filepath = path.resolve(file.history[0]);
     }
 
-    debug('Fetching local html:', 'file://' + filepath);
-    return 'file://' + filepath;
+    debug('Fetching local html:', `file://${filepath}`);
+    return `file://${filepath}`;
 }
 
 /**
@@ -141,7 +142,7 @@ function requestAsync(uri, secure = true, opts = {}) {
     debug(`Fetching resource: ${resourceUrl}`);
     const options = {rejectUnauthorized: false, headers: {}};
     if (user && pass) {
-        options.headers.Authorization = 'Basic ' + token(user, pass);
+        options.headers.Authorization = `Basic ${token(user, pass)}`;
     }
 
     if (userAgent) {
@@ -211,7 +212,7 @@ function assertLocal(filePath, opts = {}) {
  * @returns {function}
  */
 function resourcePath(htmlfile, opts) {
-    return function (filepath) {
+    return filepath => {
         if (isExternal(filepath)) {
             debug('resourcePath - remote', filepath);
             return filepath;
diff --git a/lib/gc.js b/lib/gc.js
index 01447a8a..390b4e3c 100644
--- a/lib/gc.js
+++ b/lib/gc.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const fs = require('fs-extra');
 const exitHook = require('async-exit-hook');
 const _ = require('lodash');
@@ -28,6 +29,6 @@ exitHook(done => cleanup().then(() => done()));
 process.on('cleanup', cleanup);
 
 module.exports.cleanup = cleanup;
-module.exports.addFile = function (file) {
+module.exports.addFile = file => {
     files.push(file);
 };
diff --git a/lib/vinyl-remote.js b/lib/vinyl-remote.js
index cab9eb93..91336207 100644
--- a/lib/vinyl-remote.js
+++ b/lib/vinyl-remote.js
@@ -5,6 +5,7 @@
  */
 
 'use strict';
+
 const url = require('url');
 const File = require('vinyl');
 
@@ -25,7 +26,7 @@ Object.defineProperty(File.prototype, 'remotePath', {
 
         // eslint-disable-next-line node/no-deprecated-api
         const urlObj = url.parse(remotePath);
-        remotePath = urlObj.protocol + '//' + urlObj.host + urlObj.pathname;
+        remotePath = `${urlObj.protocol}//${urlObj.host}${urlObj.pathname}`;
 
         // Record history only when path changed
         if (remotePath && remotePath !== this.remotePath) {
diff --git a/package.json b/package.json
index 513e99f3..dfe4c235 100644
--- a/package.json
+++ b/package.json
@@ -71,6 +71,14 @@
     "space": 4,
     "rules": {
       "valid-jsdoc": "off"
-    }
+    },
+    "overrides": [
+      {
+        "files": "test/*.js",
+        "envs": [
+          "mocha"
+        ]
+      }
+    ]
   }
 }
diff --git a/test/00-lib.js b/test/00-lib.js
index cdf83a67..bdd14b62 100644
--- a/test/00-lib.js
+++ b/test/00-lib.js
@@ -1,5 +1,5 @@
-/* eslint-env node, mocha */
 'use strict';
+
 const path = require('path');
 const {assert} = require('chai');
 const File = require('vinyl');
@@ -39,7 +39,7 @@ describe('Lib', () => {
             function mock(p) {
                 return new File({
                     path: 'fixtures/a/b/file.css',
-                    contents: Buffer.from('url(' + p + ')')
+                    contents: Buffer.from(`url(${p})`)
                 });
             }
 
@@ -60,7 +60,7 @@ describe('Lib', () => {
             function mock(p) {
                 return new File({
                     path: 'fixtures/a/b/file.css',
-                    contents: Buffer.from('url(' + p + ')')
+                    contents: Buffer.from(`url(${p})`)
                 });
             }
 
@@ -82,7 +82,7 @@ describe('Lib', () => {
             function mock(p) {
                 return new File({
                     path: 'fixtures/a/b/file.css',
-                    contents: Buffer.from('url(' + p + ')')
+                    contents: Buffer.from(`url(${p})`)
                 });
             }
 
@@ -103,7 +103,7 @@ describe('Lib', () => {
             function mock(p) {
                 return new File({
                     path: 'fixtures/a/file.css',
-                    contents: Buffer.from('url(' + p + ')')
+                    contents: Buffer.from(`url(${p})`)
                 });
             }
 
diff --git a/test/01-module.js b/test/01-module.js
index eb2efe90..9e4ab528 100644
--- a/test/01-module.js
+++ b/test/01-module.js
@@ -1,5 +1,5 @@
-/* eslint-env node, mocha */
 'use strict';
+
 const {assert} = require('chai');
 const critical = require('..');
 
diff --git a/test/02-generate.js b/test/02-generate.js
index cbed3713..d09a9371 100644
--- a/test/02-generate.js
+++ b/test/02-generate.js
@@ -1,5 +1,5 @@
-/* eslint-env node, mocha */
 'use strict';
+
 const path = require('path');
 const http = require('http');
 const fs = require('fs');
diff --git a/test/03-cli.js b/test/03-cli.js
index dbd49243..a3bc0617 100644
--- a/test/03-cli.js
+++ b/test/03-cli.js
@@ -1,5 +1,5 @@
-/* eslint-env node, mocha */
 'use strict';
+
 const fs = require('fs');
 const path = require('path');
 const http = require('http');
@@ -216,10 +216,10 @@ describe('CLI', () => {
             });
 
             mockery.registerMock('.', {
-                generate: function (opts) {
+                generate: opts => {
                     this.mockOpts = opts;
                     this.method = 'generate';
-                }.bind(this)
+                }
             });
         });
 
diff --git a/test/04-streams.js b/test/04-streams.js
index 39d81d8e..4ca56a4b 100644
--- a/test/04-streams.js
+++ b/test/04-streams.js
@@ -1,8 +1,9 @@
 /*
  * Unit tests for Critical.
  */
-/* eslint-env node, mocha */
+
 'use strict';
+
 const path = require('path');
 const fs = require('fs');
 const {assert} = require('chai');
diff --git a/test/helper/testhelper.js b/test/helper/testhelper.js
index 6b520e6e..85acac57 100644
--- a/test/helper/testhelper.js
+++ b/test/helper/testhelper.js
@@ -39,7 +39,7 @@ function read(file) {
  * @returns {Function}
  */
 function assertCritical(target, expected, done, skipTarget) {
-    return function (err, output) {
+    return (err, output) => {
         if (err) {
             console.log(err);
             done(err);