Update jest.md

tutorials/integration/jest.md

@@ -27,6 +27,32 @@ mocksdk.database().flush();
 // data is logged
 ```
 
+#### Demo Source
+```js
+// ./mySrc.js
+import * as admin from 'firebase-admin';
+
+const ref = admin.database().ref('myRefUrl');
+ref.on('value', function (snapshot) {
+  console.log(snapshot.val());
+});
+```
+
+#### Demo Test
+```js
+import 'jest';
+
+import firebasemock = require('firebase-mock');
+const mockdatabase = new firebasemock.MockFirebase();
+const mocksdk = firebasemock.MockFirebaseSdk(mockdatabase);
+mocksdk.initializeApp();
+
+import './mySrc.js';
+
+mocksdk.database().flush();
+// data is logged
+```
+
 ### Firestore
 
 #### Source
@@ -55,3 +81,33 @@ jest.mock('../path-to-firebase-init', () => {
 mocksdk.firestore().flush();
 // data is logged
 ```
+
+#### Demo Source
+
+```js
+// ./mySrc.js
+import * as admin from 'firebase-admin';
+
+const ref = admin.firestore().doc('users/123');
+ref.get().then(function(doc) {
+  console.log(doc.data());
+}).catch(function(err) {
+  console.error(err);
+});
+```
+
+#### Test
+
+```js
+import 'jest';
+
+import firebasemock = require('firebase-mock');
+const mockfirestore = new firebasemock.MockFirestore();
+const mocksdk = firebasemock.MockFirebaseSdk(null, null, () => mockfirestore);
+mocksdk.initializeApp();
+
+import './mySrc.js';
+
+mocksdk.firestore().flush();
+// data is logged
+```