[Composition] Test composition.add

Add test case to verify the behavior of the add method
of the composition capability.

platform/core/test/capabilities/CompositionCapabilitySpec.js

@@ -47,7 +47,7 @@ define(
             // so support that, but don't introduce complication of
             // native promises.
             function mockPromise(value) {
-                return {
+                return (value || {}).then ? value : {
                     then: function (callback) {
                         return mockPromise(callback(value));
                     }
@@ -111,6 +111,98 @@ define(
 
             });
 
+            it("allows domain objects to be added", function () {
+                var result,
+                    testModel = { composition: [] },
+                    mockChild = jasmine.createSpyObj("child", DOMAIN_OBJECT_METHODS);
+
+                mockDomainObject.getModel.andReturn(testModel);
+                mockObjectService.getObjects.andReturn(mockPromise({a: mockChild}));
+                mockChild.getCapability.andReturn(undefined);
+                mockChild.getId.andReturn('a');
+
+                mockDomainObject.useCapability.andCallFake(function (key, mutator) {
+                    if (key === 'mutation') {
+                        mutator(testModel);
+                        return mockPromise(true);
+                    }
+                });
+
+                composition.add(mockChild).then(function (domainObject) {
+                    result = domainObject;
+                });
+
+                expect(testModel.composition).toEqual(['a']);
+
+                // Should have returned the added object in its new context
+                expect(result.getId()).toEqual('a');
+                expect(result.getCapability('context')).toBeDefined();
+                expect(result.getCapability('context').getParent())
+                    .toEqual(mockDomainObject);
+            });
+
+            it("does not re-add IDs which are already present", function () {
+                var result,
+                    testModel = { composition: [ 'a' ] },
+                    mockChild = jasmine.createSpyObj("child", DOMAIN_OBJECT_METHODS);
+
+                mockDomainObject.getModel.andReturn(testModel);
+                mockObjectService.getObjects.andReturn(mockPromise({a: mockChild}));
+                mockChild.getCapability.andReturn(undefined);
+                mockChild.getId.andReturn('a');
+
+                mockDomainObject.useCapability.andCallFake(function (key, mutator) {
+                    if (key === 'mutation') {
+                        mutator(testModel);
+                        return mockPromise(true);
+                    }
+                });
+
+                composition.add(mockChild).then(function (domainObject) {
+                    result = domainObject;
+                });
+
+                // Still just 'a'
+                expect(testModel.composition).toEqual(['a']);
+
+                // Should have returned the added object in its new context
+                expect(result.getId()).toEqual('a');
+                expect(result.getCapability('context')).toBeDefined();
+                expect(result.getCapability('context').getParent())
+                    .toEqual(mockDomainObject);
+            });
+
+            it("can add objects at a specified index", function () {
+                var result,
+                    testModel = { composition: [ 'a', 'b', 'c' ] },
+                    mockChild = jasmine.createSpyObj("child", DOMAIN_OBJECT_METHODS);
+
+                mockDomainObject.getModel.andReturn(testModel);
+                mockObjectService.getObjects.andReturn(mockPromise({a: mockChild}));
+                mockChild.getCapability.andReturn(undefined);
+                mockChild.getId.andReturn('a');
+
+                mockDomainObject.useCapability.andCallFake(function (key, mutator) {
+                    if (key === 'mutation') {
+                        mutator(testModel);
+                        return mockPromise(true);
+                    }
+                });
+
+                composition.add(mockChild, 1).then(function (domainObject) {
+                    result = domainObject;
+                });
+
+                // Still just 'a'
+                expect(testModel.composition).toEqual(['b', 'a', 'c']);
+
+                // Should have returned the added object in its new context
+                expect(result.getId()).toEqual('a');
+                expect(result.getCapability('context')).toBeDefined();
+                expect(result.getCapability('context').getParent())
+                    .toEqual(mockDomainObject);
+            });
+
         });
     }
-);
+);