diff --git a/dev/vm.js b/dev/vm.js
index 98a1f7bf..363cc115 100644
--- a/dev/vm.js
+++ b/dev/vm.js
@@ -150,6 +150,13 @@ class VM {
     constructor(context={}) {
         this._urlMap = new Map();
         context.URL = createURLClass(this._urlMap);
+        context.crypto = {
+            getRandomValues: (array) => {
+                const buffer = crypto.randomBytes(array.byteLength);
+                buffer.copy(array);
+                return array;
+            }
+        };
         this._context = vm.createContext(context);
         this._assert = {
             deepStrictEqual
diff --git a/test/test-core.js b/test/test-core.js
index cf9a5c35..22392359 100644
--- a/test/test-core.js
+++ b/test/test-core.js
@@ -16,19 +16,10 @@
  */
 
 const assert = require('assert');
-const crypto = require('crypto');
 const {testMain} = require('../dev/util');
 const {VM} = require('../dev/vm');
 
-const vm = new VM({
-    crypto: {
-        getRandomValues: (array) => {
-            const buffer = crypto.randomBytes(array.byteLength);
-            buffer.copy(array);
-            return array;
-        }
-    }
-});
+const vm = new VM();
 vm.execute([
     'js/core.js'
 ]);