text: // 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.
  
  #include "ash/shelf/scoped_observer_with_duplicated_sources.h"
  
  #include "base/memory/scoped_ptr.h"
  #include "testing/gtest/include/gtest/gtest.h"
  
  class TestObserver {
   public:
    TestObserver() {}
    ~TestObserver() {}
  
   private:
    DISALLOW_COPY_AND_ASSIGN(TestObserver);
  };
  
  class TestSource {
   public:
    TestSource() : observer_count_(0) {}
    ~TestSource() {}
  
    void AddObserver(TestObserver* observer) {
      observer_count_++;
    }
    void RemoveObserver(TestObserver* observer) {
      observer_count_--;
    }
  
    int GetObserverCount() {
      return observer_count_;
    }
  
   private:
    int observer_count_;
  
    DISALLOW_COPY_AND_ASSIGN(TestSource);
  };
  
  TEST(ScopedObserverWithDuplicatedSourcesTest, DuplicatedSource) {
    TestObserver observer;
    TestSource source1;
    TestSource source2;
  
    ScopedObserverWithDuplicatedSources<TestSource, TestObserver>
        observers(&observer);
    EXPECT_EQ(0, source1.GetObserverCount());
    EXPECT_FALSE(observers.IsObserving(&source1));
    EXPECT_EQ(0, source2.GetObserverCount());
    EXPECT_FALSE(observers.IsObserving(&source2));
  
    // Add |source1|.
    observers.Add(&source1);
    EXPECT_EQ(1, source1.GetObserverCount());
    EXPECT_TRUE(observers.IsObserving(&source1));
    // AddObserver of TestSource is called only once.
    observers.Add(&source1);
    EXPECT_EQ(1, source1.GetObserverCount());
    EXPECT_TRUE(observers.IsObserving(&source1));
  
    // Add |source2|.
    observers.Add(&source2);
    EXPECT_EQ(1, source2.GetObserverCount());
    EXPECT_TRUE(observers.IsObserving(&source2));
  
    // Remove |source1|.
    observers.Remove(&source1);
    EXPECT_EQ(1, source1.GetObserverCount());
    EXPECT_TRUE(observers.IsObserving(&source1));
  
    // Remove |source2|.
    observers.Remove(&source2);
    EXPECT_EQ(0, source2.GetObserverCount());
    EXPECT_FALSE(observers.IsObserving(&source2));
  
    // Remove |source1| again.
    observers.Remove(&source1);
    // In this time, |observer| is removed from |source1|.
    EXPECT_EQ(0, source1.GetObserverCount());
    EXPECT_FALSE(observers.IsObserving(&source1));
  }
  