diff --git a/test/integration/blocks.js b/test/integration/blocks.js
index 648a321..810bcb0 100644
--- a/test/integration/blocks.js
+++ b/test/integration/blocks.js
@@ -1,4 +1,5 @@
 /* global describe, it */
+'use strict';
 
 var assert = require('assert')
 var bitcoin = require('../../')