Add unit test for Mixer::Publish.

chrome/browser/ui/app_list/search/mixer.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_UI_APP_LIST_SEARCH_MIXER_H_
 #define CHROME_BROWSER_UI_APP_LIST_SEARCH_MIXER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/ui/app_list/search/history_types.h"
 #include "ui/app_list/app_list_model.h"
 
 namespace app_list {
 
+class ChromeSearchResult;
 class SearchProvider;
 
 // Mixer collects results from providers, sorts them and publishes them to the
 // SearchResults UI model. The targeted results have 6 slots to hold the
 // result. These slots could be viewed as having three groups: main group
 // (local apps and contacts), omnibox group and web store group. The
 // main group takes no more than 4 slots. The web store takes no more than 2
 // slots. The omnibox group takes all the remaining slots.
 class Mixer {
  public:
+  // Used for sorting and mixing results.
+  struct SortData {
+    SortData();
+    SortData(ChromeSearchResult* result, double score);
+
+    bool operator<(const SortData& other) const;
+
+    ChromeSearchResult* result;  // Not owned.
+    double score;
+  };
+
   // The enum represents mixer groups. Note this must matches the order
   // of group creation in Init().
   enum GroupId {
     MAIN_GROUP = 0,
     OMNIBOX_GROUP = 1,
     WEBSTORE_GROUP = 2,
     PEOPLE_GROUP = 3,
   };
 
   explicit Mixer(AppListModel::SearchResults* ui_results);
   ~Mixer();
 
   // Creates mixer groups.
   void Init();
 
   // Associates a provider with a mixer group.
   void AddProviderToGroup(GroupId group, SearchProvider* provider);
 
   // Collects the results, sorts and publishes them.
   void MixAndPublish(const KnownResults& known_results);
 
+  // Publishes the given |results| to |ui_results|. Reuse existing ones to avoid
+  // flickering.
+  static void Publish(const std::vector<SortData>& results,

[Matt Giuca, 2014/07/08 01:48:23]

I think the standard practice here would be to make SortData and Publish private
and add MixerTest as a friend.

[calamity, 2014/07/08 04:23:00]

Done-ish. SortData still needs to be public to be constructible by the test.
Friendliness doesn't extend to subclasses.

[Matt Giuca, 2014/07/08 05:31:45]

Use FRIEND_TEST_ALL_PREFIXES to actually friend the test class, not the base
class.

+                      AppListModel::SearchResults* ui_results);
+
  private:
   class Group;
   typedef ScopedVector<Group> Groups;
 
   void FetchResults(const KnownResults& known_results);
 
   AppListModel::SearchResults* ui_results_;  // Not owned.
   Groups groups_;
 
   DISALLOW_COPY_AND_ASSIGN(Mixer);
 };
 
 }  // namespace app_list
 
 #endif  // CHROME_BROWSER_UI_APP_LIST_SEARCH_MIXER_H_