Add missing typeof

spec/api-app-spec.js

@@ -342,7 +342,7 @@ describe('app module', function () {
 
   describe('isAccessibilitySupportEnabled API', function () {
     it('returns whether the Chrome has accessibility APIs enabled', function () {
-      assert.equal(app.isAccessibilitySupportEnabled(), 'boolean')
+      assert.equal(typeof app.isAccessibilitySupportEnabled(), 'boolean')
     })
   })
 })