feat(activity): add ActivityAdapter interface

Author: lalli-flores

src/adapters/ActivityAdapter.js

@@ -0,0 +1,22 @@
+import {throwError} from 'rxjs';
+
+import WebexAdapter from './WebexAdapter';
+
+/**
+ * This is a base class that defines the interface that maps activity data.
+ * Developers that want to extend `ActivityAdapter` must implement all of its methods,
+ * adhering to the exact parameters and structure of the returned objects.
+ */
+export default class ActivityAdapter extends WebexAdapter {
+  /**
+   * Returns an observable that emits message data of the given ID.
+   *
+   * @param {string} ID  ID of the message to get.
+   * @returns {Observable.<Activity>}
+   * @memberof ActivityAdapter
+   */
+  // eslint-disable-next-line no-unused-vars
+  getMessage(ID) {
+    return throwError(new Error('getMessage(ID) must be defined in ActivityAdapter'));
+  }
+}

src/adapters/ActivityAdapter.test.js

@@ -0,0 +1,27 @@
+import ActivityAdapter from './ActivityAdapter';
+
+describe('Activity Adapter Interface', () => {
+  let activityAdapter;
+
+  beforeEach(() => {
+    activityAdapter = new ActivityAdapter();
+  });
+
+  test('getMessage() returns an observable', () => {
+    expect(rxjs.isObservable(activityAdapter.getMessage())).toBeTruthy();
+  });
+
+  test('getMessage() throws a proper error message', (done) => {
+    activityAdapter.getMessage('msgID').subscribe(
+      () => {},
+      (error) => {
+        expect(error.message).toBe('getMessage(ID) must be defined in ActivityAdapter');
+        done();
+      }
+    );
+  });
+
+  afterEach(() => {
+    activityAdapter = null;
+  });
+});