Refactor Day04 and Day09 to rename methods and variables for improved clarity and update Day09 tests with additional input file and test case

AoC_2025.Tests/Day09Test.cs

@@ -7,6 +7,7 @@ public class Day09Test
     private IPuzzleSolver<long> _sut;
     private static readonly string rootPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
     private readonly string TestInputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Test\day09.txt";
+    private readonly string Test2InputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Test\day09_2.txt";
     private readonly string ProdInputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Prod\day09.txt";
     
     public Day09Test()
@@ -37,6 +38,15 @@ public class Day09Test
         Assert.Equal(24, actual);
     }
     
+    [Fact]
+    public void Part02_Test2_equals_30()
+    {
+        // todo: color edges as right, left, up, down to only allow rectangles between right and left or up and down edges
+        var actual = _sut.SolvePart2(Test2InputPath);
+        
+        Assert.Equal(30, actual);
+    }
+    
     [Fact]
     public void Part02_Prod_equals_1568849600()
     {