CODEWITHSUNDEEP
.netunit-testinginterface
FrenkyB
FrenkyB

Reputation: 7197

How to resolve hidden dependency with interface

I have a code, where chessboard and piece are injected with interfaces. DiagonalDirections is enumeration. So far, so good. I don't inject dependencies, neither I use hidded dependencies. 

private void addToAllowedPositions(IChessboard chessboard, IPiece piece, DiagonalDirections direction)
    {
        int horizontalIndex = piece.Position.IndexHorizontal;
        int verticalIndex = piece.Position.IndexVertical;
        while (AreIndexesValid(setHorizontalIndexDirection(direction, ref horizontalIndex), setVerticalIndexDirection(direction, ref verticalIndex)))
        {
            IPosition currentPosition = new Position(horizontalIndex, verticalIndex);
            IPiece currentPiece = chessboard.GetPiece(currentPosition);
            if (currentPiece == null)
                 {
                     allowedPositions.Add(currentPosition);
                 }
            else if (currentPiece.Color != piece.Color)
                 {
                     allowedPositions.Add(currentPosition);
                     break;
                 }
                 else break;
         }
    }

Problem is with this line of code:

IPosition currentPosition = new Position(horizontalIndex, verticalIndex);

I really don't know how can I use interface here? New Position must be created each time. That is my only dependency, which I don't know how to isolate. I also have a problem, when I want to unit test this piece of code. If anything is changed in Position class, it is immediately being reflected also in this method, on existing unit tests.

Upvotes: 1

Views: 151

Answers (1)

Mark Cidade
Mark Cidade

Reputation: 99957

You can add a factory method to the IChessboard interface:

IPosition currentPosition = chessboard.CreatePosition(horizontalIndex, verticalIndex);

Upvotes: 2

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