Lazily access the puzzle input to avoid querying it when testing with the example

Author: pBouillon

src/AdventOfCode.Commons/Solver.cs

@@ -18,16 +18,19 @@ public abstract class Solver<TInput, TResult>
     /// <summary>
     /// The puzzle input
     /// </summary>
-    public readonly TInput PuzzleInput;
+    public readonly Lazy<TInput> PuzzleInput;
 
     /// <summary>
     /// Create a new solver and initialize its puzzle input based on the provided <see cref="IPuzzleInputReaderStrategy"/>
     /// </summary>
     /// <param name="puzzleInputReader">The strategy to use to retriever the puzzle input</param>
     private Solver(IPuzzleInputReaderStrategy puzzleInputReader)
     {
-        var content = puzzleInputReader.ReadInput();
-        PuzzleInput = ParseInput(content);
+        PuzzleInput = new Lazy<TInput>(() =>
+        {
+            var content = puzzleInputReader.ReadInput();
+            return ParseInput(content);
+        });
     }
 
     /// <summary>

src/AdventOfCode.Commons/TestEngine.cs

@@ -101,7 +101,7 @@ public void PartOneSolutionTest()
         var input = _solver.PuzzleInput;
 
         // Act
-        var result = _solver.PartOne(input);
+        var result = _solver.PartOne(input.Value);
 
         // Assert
         result.Should().Be(PartOne.Solution);
@@ -137,7 +137,7 @@ public void PartTwoSolutionTest()
         var input = _solver.PuzzleInput;
 
         // Act
-        var result = _solver.PartTwo(input);
+        var result = _solver.PartTwo(input.Value);
 
         // Assert
         result.Should().Be(PartTwo.Solution);