public void AttackedFrom_WhteRookE1KnightC3C4BlackRookA4TargetE4_ReturnsBitboardC3E1() { // arrange var white = new Side( "G1", new PieceSet<Queen>(), new PieceSet<Bishop>(), new PieceSet<Knight>(Bitboard.With.C3.C4), new PieceSet<Rook>(Bitboard.With.E1), new WhitePawns() ); var black = new Side( "G8", new PieceSet<Queen>(), new PieceSet<Bishop>(), new PieceSet<Knight>(), new PieceSet<Rook>(Bitboard.With.A4), new BlackPawns() ); var target = new Square("E4"); var expected = Bitboard.With.C3.E1.Build(); // act var result = target.AttackedFrom(white, black); // assert result.Should().Be(expected); }