Update article.md

Author: leviding

1-js/03-code-quality/05-testing-mocha/article.md

@@ -159,7 +159,7 @@ We can select one of two ways to organize the test here:
         assert.equal(pow(2, 3), 8);
       });
 
-      it("3 raised to power 3 is 27", function() {
+      it("3 raised to power 4 is 81", function() {
         assert.equal(pow(3, 4), 81);
       });
 
@@ -182,7 +182,7 @@ The result:
 
 [iframe height=250 src="pow-2" edit border="1"]
 
-As we could expect, the second test failed. Sure, our function always returns `8`, while the `assert` expects `27`.
+As we could expect, the second test failed. Sure, our function always returns `8`, while the `assert` expects `81`.
 
 ## Improving the implementation