[Forms] Add specs, doc for CompositeController

Add spec and in-line documentation for CompositeController,
introduced to support integration of forms with the Create
menu, WTD-593.

platform/forms/test/controllers/CompositeControllerSpec.js

@@ -0,0 +1,36 @@
+/*global define,describe,it,expect,beforeEach,waitsFor,jasmine*/
+
+define(
+    ["../../src/controllers/CompositeController"],
+    function (CompositeController) {
+        "use strict";
+
+        describe("The composite controller", function () {
+            var controller;
+
+            beforeEach(function () {
+                controller = new CompositeController();
+            });
+
+            it("detects non-empty arrays", function () {
+                expect(controller.isNonEmpty(["a", "b", undefined]))
+                    .toBeTruthy();
+                expect(controller.isNonEmpty([3]))
+                    .toBeTruthy();
+            });
+
+            it("detects empty arrays", function () {
+                expect(controller.isNonEmpty([undefined, undefined, undefined]))
+                    .toBeFalsy();
+                expect(controller.isNonEmpty([]))
+                    .toBeFalsy();
+            });
+
+            it("ignores non-arrays", function () {
+                expect(controller.isNonEmpty("this is not an array"))
+                    .toBeFalsy();
+            });
+
+        });
+    }
+);