diff --git a/.istanbul.yml b/.istanbul.yml
index 5830ddb662..6489c5aeff 100644
--- a/.istanbul.yml
+++ b/.istanbul.yml
@@ -1,3 +1,5 @@
 instrumentation:
   root: .
-  excludes: "**/node_modules/**"
+  excludes:
+    - "**/node_modules/**"
+    - "scripts/*.js"
diff --git a/package.json b/package.json
index da4f821f30..10dcf91c0c 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
     "babel-plugin-transform-runtime": "^6.3.13",
     "babel-preset-es2015": "^6.13.2",
     "babel-preset-stage-0": "^6.0.0",
+    "babel-register": "^6.14.0",
     "babel-runtime": "^6.0.0",
     "browserify": "^11.2.0",
     "bundle-collapser": "^1.2.1",
diff --git a/packages/babel-cli/test/index.js b/packages/babel-cli/test/index.js
index f5dbe30232..a0c7d365c2 100644
--- a/packages/babel-cli/test/index.js
+++ b/packages/babel-cli/test/index.js
@@ -1,5 +1,3 @@
-if (process.env.running_under_istanbul) return;
-
 var readdir        = require("fs-readdir-recursive");
 var helper         = require("babel-helper-fixtures");
 var assert         = require("assert");
@@ -79,7 +77,6 @@ var buildTest = function (binName, testName, opts) {
   var binLoc = path.join(__dirname, "../lib", binName);
 
   return function (callback) {
-    this.timeout(5000);
     clear();
     saveInFiles(opts.inFiles);
 
diff --git a/packages/babel-core/test/option-manager.js b/packages/babel-core/test/option-manager.js
index d6488b154d..39231b7c98 100644
--- a/packages/babel-core/test/option-manager.js
+++ b/packages/babel-core/test/option-manager.js
@@ -1,29 +1,22 @@
-var assert = require("assert");
-var OptionManager = require("../lib/transformation/file/options/option-manager");
-var Logger = require("../lib/transformation/file/logger");
-var path = require("path");
+import assert from "assert";
+import OptionManager from "../lib/transformation/file/options/option-manager";
+import Logger from "../lib/transformation/file/logger";
+import path from "path";
 
-suite("option-manager", function () {
-  suite("memoisePluginContainer", function () {
-    test("throws for babel 5 plugin", function() {
+suite("option-manager", () => {
+  suite("memoisePluginContainer", () => {
+    test("throws for babel 5 plugin", () => {
       return assert.throws(
-        function () {
-          OptionManager.memoisePluginContainer(
-            function (ref) {
-              var Plugin = ref.Plugin;
-              return new Plugin("object-assign", {});
-            }
-          );
-        },
+        () => OptionManager.memoisePluginContainer(({ Plugin }) => new Plugin("object-assign", {})),
         /Babel 5 plugin is being run with Babel 6/
       );
     })
   });
 
-  suite("mergeOptions", function () {
-    test("throws for removed babel 5 options", function() {
+  suite("mergeOptions", () => {
+    test("throws for removed babel 5 options", () => {
       return assert.throws(
-        function () {
+        () => {
           var opt = new OptionManager(new Logger(null, "unknown"));
           opt.init({
             'randomOption': true
@@ -33,9 +26,9 @@ suite("option-manager", function () {
       );
     });
 
-    test("throws for removed babel 5 options", function() {
+    test("throws for removed babel 5 options", () => {
       return assert.throws(
-        function () {
+        () => {
           var opt = new OptionManager(new Logger(null, "unknown"));
           opt.init({
             'auxiliaryComment': true,
@@ -46,9 +39,9 @@ suite("option-manager", function () {
       );
     });
 
-    test("throws for resolved but erroring preset", function() {
+    test("throws for resolved but erroring preset", () => {
       return assert.throws(
-        function () {
+        () => {
           var opt = new OptionManager(new Logger(null, "unknown"));
           opt.init({
             'presets': [path.join(__dirname, "fixtures/option-manager/not-a-preset")]
diff --git a/scripts/babel-register.js b/scripts/babel-register.js
new file mode 100644
index 0000000000..aae4caa1b4
--- /dev/null
+++ b/scripts/babel-register.js
@@ -0,0 +1,23 @@
+var babel = require("../package.json").babel;
+var register = require("babel-register");
+var path = require("path");
+
+if (babel.plugins) {
+  // correct path of relative plugins
+  babel.plugins = babel.plugins.map(function (plugin) {
+    if (plugin.charAt(0) === '.') {
+      return plugin.replace(/^\./, path.join(__dirname, '..'));
+    }
+
+    return plugin;
+  });
+}
+
+register(babel);
+register({
+  extensions: [".js"],
+  // Only js files in the test folder but not in the subfolder fixtures.
+  only: /packages\/.+\/test\/(?!fixtures\/).+\.js$/,
+  babelrc: false,
+  compact: true,
+});
diff --git a/test/mocha.opts b/test/mocha.opts
index 2267a63e68..b4b84465b2 100644
--- a/test/mocha.opts
+++ b/test/mocha.opts
@@ -1 +1 @@
---reporter dot --ui tdd --timeout 10000
+--reporter dot --ui tdd --timeout 10000 --compilers js:./scripts/babel-register