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Implement this second test

Code Block

language	java

   @Test
   public void find_heighest_score_with_array_of_one_return_array_of_one()
   {
       // Arrange
       int[] scores = { 56, 67, 45, 89 };
       String topicName = "Physics";
       ArrayList<TopicScores> topicScores = new ArrayList<>();
       topicScores.add(new TopicScores(topicName, scores));
   
       TopicManager cut = new TopicManager();
       ArrayList<TopicTopScore> expectedResult = new ArrayList<>();
       expectedResult.add(new TopicTopScore(topicName, 89));

       // Act
       ArrayList<TopicTopScore> result = cut.findTopicHighScores(topicScores);

       assertEquals(expectedResult.get(0).getTopicName(), result.get(0).getTopicName());
       assertEquals(expectedResult.get(0).getTopScore(), result.get(0).getTopScore() );
   }

And here is the implementation class

Code Block

language	c#java

class TopicManager
{
   private final HighestNumberFinder highestNumberFinder = new HighestNumberFinder();

   ArrayList<TopicTopScore> findTopicHighScores(ArrayList<TopicScores> array)
   {
      ArrayList<TopicTopScore> topScores = new ArrayList<>();

      if(array.size() == 1)
      {
          TopicScores ts = array.get(0);
          int topScore = highestNumberFinder.findHighestNumber(ts.getScores());

          topScores.add(new TopicTopScore(ts.getTopicName(), topScore));
      }
      return topScores;
   }
}

Updated TopicScores.java

Code Block

language	java

package com.s2s.demos.topicmanager;

public class TopicScores
{
   private String topicName;
   private int[] scores;
   
   public TopicScores(String topicName, int[] scores)
   {
      this.topicName = topicName;
      this.scores = scores;
   }
   
   public String   getTopicName()
   {
      return topicName;
   }
   
   public   int[] getScores()
   {
      return scores;
   }
}

Updated TopicTopScores.java

Code Block

language	java

public class TopicTopScore
{
   private  String topicName;
   private  int topScore;

   public TopicTopScore(String topicName, int score)
   {
      this.topScore = score;
      this.topicName = topicName;
   }
   
   public String getTopicName()
   {
      return topicName;
   }

   public int getTopScore()
   {
      return topScore;
   }
}

Looking back at TopicManager, Line 3 represents the elephant in the code
1. We already have tests for the HighestNumberFinder class, and yes class TopicManager requires HighestNumberFinder. But the coupling between these two classes is such that we cannot test TopicManger independently of HighestNumberFinder. Actually, this is a code smell.
2. we can not substitute out HighestNumberFinder, this also is a code smell.
3. We can remove the code smell by injecting HighestNumberFinder into TopicManager, when TopicManager is created.
Modify TopicManager as follows
1. remove the creation of HighestNumberFinder at line 5
2. Pass an instance of a HighestNumberFinder into TopicManager as a constructor parameter

Code Block

language	c#java

public class TopicManager
{
    private HighestNumberFinder highestNumberFinder;

    public  TopicManager( HighestNumberFinder hnf )
    {
        highestNumberFinder = hnf;
    }

    public TopicTopScore[] findTopicHighScores(TopicScores[] array)
    {
        if(array.Length == 1)
        {
            List<TopicTopScore> topScores = new List<TopicTopScore>();

            TopicScores ts = array[0];
            int topScore = highestNumberFinder.findHighestNumber(ts.Scores);

            topScores.Add(new TopicTopScore(ts.TopicName, topScore));

            return topScores.ToArray();
        }
        else
            return Array.Empty<TopicTopScore>();
    }
}

Refactor the tests so that they run. You should not have to change any of the test data.

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Old Version 10

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