public void ShouldMarkCellsWithShip() { var shipPlacement = _fixture.Create <ShipPlacement>(); var shipPositions = _fixture.CreateMany <(char, int)>().ToList(); _battleshipPlacement.Setup(x => x.GetShipPositions(shipPlacement)) .Returns(shipPositions); _battleship.Place(_battlefield.Object, shipPlacement); foreach (var positions in shipPositions) { _battlefield.Verify(x => x.MarkCell(positions), Times.Once); } _battlefield.Verify(x => x.MarkCell(It.IsAny <(char, int)>()), Times.Exactly(shipPositions.Count)); }