MD Bookmarks: Batch updates to the UI when processing deletes and moves

chrome/test/data/webui/md_bookmarks/store_client_test.js

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-suite('bookmarks.StoreClient', function() {
-  var store;
-  var client;
-
-  function update(newState) {
-    store.notifyObservers_(newState);
-    Polymer.dom.flush();
-  }
-
-  function getRenderedItems() {
-    return Array.from(client.root.querySelectorAll('.item'))
-        .map((div) => div.textContent.trim());
-  }
-
-  suiteSetup(function() {
-    document.body.innerHTML = `
-      <dom-module is="test-store-client">
-        <template>
-          <template is="dom-repeat" items="[[items]]">
-            <div class="item">[[item]]</div>
-          </template>
-        </template>
-      </dom-module>
-    `;
-
-    Polymer({
-      is: 'test-store-client',
-
-      behaviors: [bookmarks.StoreClient],
-
-      properties: {
-        items: {
-          type: Array,
-          observer: 'itemsChanged_',
-        },
-      },
-
-      attached: function() {
-        this.hasChanged = false;
-        this.watch('items', function(state) {
-          return state.items;
-        });
-        this.updateFromStore();
-      },
-
-      itemsChanged_: function(newItems, oldItems) {
-        if (oldItems)
-          this.hasChanged = true;
-      },
-    });
-  });
-
-  setup(function() {
-    PolymerTest.clearBody();
-
-    // Reset store instance:
-    bookmarks.Store.instance_ = new bookmarks.Store();
-    store = bookmarks.Store.getInstance();
-    store.init({
-      items: ['apple', 'banana', 'cantaloupe'],
-      count: 3,
-    });
-
-    client = document.createElement('test-store-client');
-    document.body.appendChild(client);
-    Polymer.dom.flush();
-  });
-
-  test('renders initial data', function() {
-    assertDeepEquals(['apple', 'banana', 'cantaloupe'], getRenderedItems());
-  });
-
-  test('renders changes to watched state', function() {
-    var newItems = ['apple', 'banana', 'courgette', 'durian'];
-    var newState = Object.assign({}, store.data, {
-      items: newItems,
-    });
-    update(newState);
-
-    assertTrue(client.hasChanged);
-    assertDeepEquals(newItems, getRenderedItems());
-  });
-
-  test('ignores changes to other subtrees', function() {
-    var newState = Object.assign({}, store.data, {count: 2});
-    update(newState);
-
-    assertFalse(client.hasChanged);
-  });
-});