MD Bookmarks: Prevent flash of folder contents when changing search term

chrome/test/data/webui/md_bookmarks/reducers_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('selection state', function() {
   var selection;
   var action;
 
   function select(items, anchor, clear, toggle) {
     return {
@@ skipping 418 matching lines @@
     // Case 1: Clear search by setting an empty search term.
     action = bookmarks.actions.setSearchTerm('');
     var clearedState = bookmarks.reduceAction(searchedState, action);
 
     // Should go back to displaying the contents of '2', which was shown before
     // the search.
     assertEquals('2', clearedState.selectedFolder);
     assertFalse(bookmarks.util.isShowingSearch(clearedState));
     assertDeepEquals(['3'], bookmarks.util.getDisplayedList(clearedState));
     assertEquals('', clearedState.search.term);
-    assertDeepEquals([], clearedState.search.results);
+    assertDeepEquals(null, clearedState.search.results);
 
     // Case 2: Clear search by selecting a new folder.
     action = bookmarks.actions.selectFolder('1');
     var selectedState = bookmarks.reduceAction(searchedState, action);
 
     assertEquals('1', selectedState.selectedFolder);
     assertFalse(bookmarks.util.isShowingSearch(selectedState));
     assertDeepEquals(['2'], bookmarks.util.getDisplayedList(selectedState));
     assertEquals('', selectedState.search.term);
-    assertDeepEquals([], selectedState.search.results);
+    assertDeepEquals(null, selectedState.search.results);
+  });
+
+  test('results do not clear while performing a second search', function() {
+    action = bookmarks.actions.setSearchTerm('te');
+    state = bookmarks.reduceAction(state, action);
+
+    assertFalse(bookmarks.util.isShowingSearch(state));
+
+    action = bookmarks.actions.setSearchResults(['2', '3']);
+    state = bookmarks.reduceAction(state, action);
+
+    assertFalse(state.search.inProgress);
+    assertTrue(bookmarks.util.isShowingSearch(state));
+
+    // Continuing the search should not clear the previous results, which should
+    // continue to show until the new results arrive.
+    action = bookmarks.actions.setSearchTerm('test');
+    state = bookmarks.reduceAction(state, action);
+
+    assertTrue(state.search.inProgress);
+    assertTrue(bookmarks.util.isShowingSearch(state));
+    assertDeepEquals(['2', '3'], bookmarks.util.getDisplayedList(state));
+
+    action = bookmarks.actions.setSearchResults(['3']);
+    state = bookmarks.reduceAction(state, action);
+
+    assertFalse(state.search.inProgress);
+    assertTrue(bookmarks.util.isShowingSearch(state));
+    assertDeepEquals(['3'], bookmarks.util.getDisplayedList(state));
   });
 
   test('removes deleted nodes', function() {
     var action;
 
     action = bookmarks.actions.setSearchTerm('test');
     state = bookmarks.reduceAction(state, action);
 
     action = bookmarks.actions.setSearchResults(['1', '3', '2']);
     state = bookmarks.reduceAction(state, action);
 
     action = bookmarks.actions.removeBookmark('2', '1', 0, state.nodes);
     state = bookmarks.reduceAction(state, action);
 
     // 2 and 3 should be removed, since 2 was deleted and 3 was a descendant of
     // 2.
     assertDeepEquals(['1'], state.search.results);
   });
 });