AdventOfCode2018: Move tests to the corresponding day

AdventOfCode2018.Tests/Day09_Tests.cs

@@ -2,6 +2,76 @@
 
 public class Day09_Tests
 {
+    #region MarbleGame_PlayGame
+    
+    [Fact]
+    public void MarbleGame_PlayGame__Test1()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(9, 25);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(32, highScore);
+    }
+
+    [Fact]
+    public void MarbleGame_PlayGame__Test2()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(10, 1618);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(8317, highScore);
+    }
+
+    [Fact]
+    public void MarbleGame_PlayGame__Test3()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(13, 7999);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(146373, highScore);
+    }
+
+    [Fact]
+    public void MarbleGame_PlayGame__Test4()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(17, 1104);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(2764, highScore);
+    }
+
+    [Fact]
+    public void MarbleGame_PlayGame__Test5()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(21, 6111);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(54718, highScore);
+    }
+
+    [Fact]
+    public void MarbleGame_PlayGame__Test6()
+    {
+        Day09.MarbleGame marbleGame = new();
+
+        marbleGame.PlayGame(30, 5807);
+        long highScore = marbleGame.GetHighScore();
+
+        Assert.Equal(37305, highScore);
+    }
+    
+    #endregion MarbleGame_PlayGame
+    
     [Fact]
     public void ResolvePart1__Test1()
     {