Done, got help from Katrina and Leon

PlaylistChallenge.iml

@@ -13,5 +13,7 @@
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
     <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
   </component>
 </module>

src/main/java/io/zipcoder/Music.java

@@ -1,14 +1,61 @@
 package io.zipcoder;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 public class Music {
 
     private String[] playList;
 
-    public Music(String[] playList){
-        this.playList = playList;
-    }
+    public Music(String[] playList)
+    {this.playList = playList;}
+
+    public Integer selection(Integer startIndex, String selection)
+    {
+        //Use an ArrayList
+        List<String> songList = Arrays.asList(this.playList);
+
+        /*The formula for forward takes the index of the selection
+         and minus the startIndex then Math.abs*/
+        int indexOfSelection = songList.indexOf(selection);
+        int indexDifference = indexOfSelection - startIndex;
+        int forwardClicks = Math.abs(indexDifference);
+
+        /*The formula for backwardClicks adds the size of the array plus the startIndex
+         * and subtracts the last index of the array. In essance it finds the distance without
+         * physically looping backwards */
+        int listSize = songList.size();
+        int sizePlusStart = listSize + startIndex;
+        int lastIndexOfSelection = songList.lastIndexOf(selection);
+        int backwardClicks = Math.abs(sizePlusStart) - lastIndexOfSelection;
+
+
+        //then compares the two values for backwardClicks and forwardClicks and returns the minimum
+        return Math.min(forwardClicks, backwardClicks);
+
+    }}
 
-    public Integer selection(Integer startIndex, String selection){
-        return null;
-    }
-}
+////    public Integer selectionn(Integer startIndex, String selection)
+////    {
+////        //Use an ArrayList
+////        ArrayList<String> songList = new ArrayList<String>(Arrays.asList(this.playList));
+////
+////        /*The formula for forward takes the index of the selection
+////         and minus the startIndex then Math.abs*/
+////
+////        int forwardClicks = Math.abs(songList.indexOf(selection) - startIndex);
+////
+////        /*The formula for backwardClicks adds the size of the array plus the startIndex
+////         * and subtracts the last index of the array. In essance it finds the distance without
+////         * physically looping backwards */
+////
+////        int backwardClicks = Math.abs(songList.size() + startIndex) - (songList.lastIndexOf(selection));
+////
+////
+////        //then compares the two values for backwardClicks and forwardClicks and returns the minimum
+////
+////        return Math.min(forwardClicks, backwardClicks);
+////
+////    }
+//}

src/test/java/io/zipcoder/MusicTest.java

@@ -6,9 +6,9 @@
 public class MusicTest {
 
     @Test
-    public void selectionTest1(){
+    public void selectionTest1() {
 
-        String[] playlist = {"wheniseeyouagain","borntorun","nothingelsematters","cecelia"};
+        String[] playlist = {"wheniseeyouagain", "borntorun", "nothingelsematters", "cecelia"};
         Music music = new Music(playlist);
         Integer startingIndex = 1;
         String selection = "cecelia";
@@ -18,14 +18,36 @@ public void selectionTest1(){
     }
 
     @Test
-    public void selectionTest2(){
+    public void selectionTest2() {
 
-        String[] playlist = {"dancinginthedark","rio","liveoak","liveoak"};
+        String[] playlist = {"dancinginthedark", "rio", "liveoak", "liveoak"};
         Music music = new Music(playlist);
         Integer startingIndex = 0;
         String selection = "liveoak";
         Integer expected = 1;
         Integer actual = music.selection(startingIndex, selection);
         Assert.assertEquals(expected, actual);
     }
-}
+
+    @Test
+    public void selectionTest3() {
+        String[] playList = {"Changes", "I Will Always Love You", "Trap Queen", "Changes", "Can't Be Touched"};
+        Music music = new Music(playList);
+        Integer startingIndex = 1;
+        String selection = "Changes";
+        Integer expected = 1;
+        Integer actual = music.selection(startingIndex, selection);
+        Assert.assertEquals(expected, actual); }
+
+    @Test
+    public void selectionTest4()
+    {
+        String [] playList = {"Changes", "I Will Always Love You", "Trap Queen", "You Came To Do This", "I Miss You", "Changes"};
+        Music music = new Music(playList);
+        Integer startingIndex = 2;
+        String selection = "Changes";
+        Integer expected = 2;
+        Integer actual = music.selection(startingIndex, selection);
+        Assert.assertEquals(expected, actual);
+    }
+}