diff --git a/.eslintignore b/.eslintignore
index 7db9266305..ede7dfff5c 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -2,3 +2,4 @@
 **/vendor/**/*.js
 django/contrib/gis/templates/**/*.js
 node_modules/**.js
+tests/**/*.js
diff --git a/Gruntfile.js b/Gruntfile.js
index 2bf8a10c81..2d99041cb8 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -1,4 +1,6 @@
-var globalThreshold = 50;  // Global code coverage threshold (as a percentage)
+'use strict';
+
+const globalThreshold = 50; // Global code coverage threshold (as a percentage)
 
 module.exports = function(grunt) {
     grunt.initConfig({