chainAsync update: last function shouldn't get 'next' as argument

Confident that my tests pass, but _30.js won't update.

test/chainAsync.test.js

@@ -5,18 +5,30 @@ test('chainAsync is a Function', () => {
   expect(chainAsync).toBeInstanceOf(Function);
 });
 
+let incrementer = 0
 test('Calls all functions in an array', () => {
+  chainAsync([
+    next => {
+      incrementer += 1
+      next();
+    },
+    next => {
+      incrementer += 1
+      next();
+    },
+    next => {
+      expect(incrementer).toEqual(2);
+    }
+  ]);
+});
+
+test('Last function does not receive "next" argument', () => {
   chainAsync([
     next => {
       next();
     },
     next => {
-      (() => {
-        next();
-      })();
-    },
-    next => {
-      expect(true).toBeTruthy();
+      expect(next).toBe(null);
     }
   ]);
-});
+})