test(vgPlaybackButton): Raise coverage. Initial unit tests

#1 Raise coverage to 100%

src/vg-controls/vg-playback-button/vg-playback-button.spec.ts

@@ -0,0 +1,96 @@
+import {it, describe, expect, beforeEach, inject} from 'angular2/testing';
+import {VgPlaybackButton} from "./vg-playback-button";
+import {VgAPI} from "../../services/vg-api";
+import {ElementRef} from "angular2/core";
+
+describe('Play/Pause Button', () => {
+    let playbackButton:VgPlaybackButton;
+    let ref:ElementRef;
+    let api:VgAPI;
+
+    beforeEach(() => {
+        ref = {
+            nativeElement: {
+                getAttribute: (name) => {
+                    return name;
+                }
+            }
+        };
+
+        api = new VgAPI();
+        api.medias = {
+            main: {
+                state: 'play'
+            },
+            secondary: {
+                state: 'pause'
+            }
+        };
+
+
+        playbackButton = new VgPlaybackButton(ref, api);
+    });
+
+    it('Should set playbackIndex default value to 1', () => {
+        expect(playbackButton.playbackIndex).toEqual(1);
+    });
+
+    it('Should get media by id on init', () => {
+        spyOn(playbackButton.elem, 'getAttribute').and.callThrough();
+        spyOn(api, 'getMediaById').and.callFake(() => {
+            return {
+                volume: 1
+            };
+        });
+
+        playbackButton.ngOnInit();
+
+        expect(playbackButton.elem.getAttribute).toHaveBeenCalledWith('vg-for');
+        expect(api.getMediaById).toHaveBeenCalledWith('vg-for');
+    });
+
+    describe('onClick (single and multiple media)', () => {
+        it('should increase playbackIndex', () => {
+            api.medias = {
+                main: {
+                    state: 'play'
+                }
+            };
+
+            playbackButton.target = api;
+
+            playbackButton.onClick();
+
+            expect(playbackButton.playbackIndex).toEqual(2);
+        });
+
+        it('should set playbackRate to target media', () => {
+            api.medias = {
+                main: {
+                    state: 'play'
+                }
+            };
+
+            playbackButton.target = api;
+
+            playbackButton.onClick();
+
+            expect(playbackButton.target.playbackRate).toEqual('1.5');
+        });
+
+        it('should set playbackRate to target media', () => {
+            let media = {
+                playbackRate: {
+                    test: '1'
+                }
+            };
+
+            playbackButton.target = media;
+            playbackButton.vgFor = 'test';
+
+            playbackButton.onClick();
+
+            expect(playbackButton.target.playbackRate.test).toEqual('1.5');
+        });
+    });
+});