diff --git a/lib/index.js b/lib/index.js
index d8d6eb04..0f80b8aa 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -30,11 +30,11 @@ function getContext() {
     }        
 
     if (typeof navigator !== 'undefined') {
-        if (navigator.product === 'ReactNative') {
+        if (navigator.product === 'ReactNative') { // eslint-disable-line no-undef
             return 'reactnative';
         }
 
-        if (/Chrome/.test(navigator.userAgent)) {
+        if (/Chrome/.test(navigator.userAgent)) { // eslint-disable-line no-undef
             return 'chromedebugger';
         }
     }
diff --git a/tests/js/async-tests.js b/tests/js/async-tests.js
index f5c0b759..fa341bb7 100644
--- a/tests/js/async-tests.js
+++ b/tests/js/async-tests.js
@@ -29,7 +29,7 @@ function createNotificationTest(config, getObservable, addListener, removeListen
     return new Promise((resolve, reject) => {
         let realm = new Realm(config);
         let observable = getObservable(realm);
-        let worker = new Worker(__dirname + '/worker-tests-script.js', [REALM_MODULE_PATH]);
+        let worker = new Worker(__dirname + '/worker-tests-script.js', [REALM_MODULE_PATH]); // eslint-disable-line no-undef 
 
         // Test will fail if it does not receive a change event within a second.
         let timer = setTimeout(() => {
diff --git a/tests/spec/helpers/mock_realm.js b/tests/spec/helpers/mock_realm.js
index f5673be2..d0a11499 100644
--- a/tests/spec/helpers/mock_realm.js
+++ b/tests/spec/helpers/mock_realm.js
@@ -12,5 +12,5 @@ module.exports = function(realmModulePath) {
         warnOnReplace: false,
         warnOnUnregistered: false
     });
-    mockery.registerSubstitute('realm', REALM_MODULE_PATH);
+    mockery.registerSubstitute('realm', REALM_MODULE_PATH); // eslint-disable-line no-undef
 }
diff --git a/tests/spec/helpers/setup-module-path.js b/tests/spec/helpers/setup-module-path.js
index faf32f4c..5ab4ac3f 100644
--- a/tests/spec/helpers/setup-module-path.js
+++ b/tests/spec/helpers/setup-module-path.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const mock_helper = require('./mock_realm')
 const path = require('path');