public void CompletePuzzle()
{
var puzzle = new Puzzle(_board);
puzzle.AddSolver(new NakedSinglesSolver());
Assert.True(puzzle.SolvePuzzle() && puzzle.ToString() == _completeBoard, "Puzzle should be solved.");
}
public void AttemptToSolveCompletedPuzzle()
{
var puzzle = new Puzzle(_board);
puzzle.AddSolver(new NakedSinglesSolver());
Assert.False(puzzle.TrySolve(out Solution solution), "No more solutions should be available.");
Assert.True(puzzle.SolvePuzzle(), "Puzzle should be solved.");
}