diff --git a/spec/test/chachaSpec.js b/spec/test/chachaSpec.js
--- a/spec/test/chachaSpec.js
+++ b/spec/test/chachaSpec.js
@@ -1,5 +1,17 @@
 /* global expect */
 
+function getRandomValues(arr){
+	for(let i=0;i<arr.length;i++){
+		arr[i]=Math.floor(Math.random()*256);
+	}
+}
+
+window={
+	crypto: {
+		getRandomValues: getRandomValues
+	}
+};
+
 describe("Chacha",function(){
 	let cryptoJS=require("../../dist/main.js");
 	let util=cryptoJS.util;
@@ -43,9 +55,7 @@ describe("Chacha",function(){
 			let text=str2utf8(plaintext);
 			let key=[];
 			for(let i=0;i<16;i++){key.push(Math.floor(Math.random()*256));}
-			let nonce=[];
-			for(let i=0;i<8;i++){nonce.push(Math.floor(Math.random()*256));}
-			let [_,ciphertext]=encrypt(text,key,nonce);
+			let [nonce,ciphertext]=encrypt(text,key);
 			expect(decrypt(ciphertext,key,nonce)).toEqual(text);
 		});
 	});