Add Unit Tests for Pipes

Ref #7

src/common/pipes.spec.ts

@@ -0,0 +1,16 @@
+import {KeysPipe} from "./pipes";
+
+describe('KeysPipe: ', () => {
+  let keysPipe: KeysPipe;
+
+  beforeEach(() => {
+    keysPipe = new KeysPipe();
+  });
+
+  it('All keys of Objetc are returned', () => {
+    let testObject = {keyOne: 'Key is one', keyTwo: 'Key is two', keyThree: 'Key is three'};
+
+    expect(keysPipe.transform(testObject, [])).toEqual( ['keyOne', 'keyTwo', 'keyThree']);
+  });
+
+});