public void WhenIMarkAPosition_ItShouldNotBeBlank(Positions3X3 position)
 {
     _grid = Mark.Cross.On(_grid, position);
     Assert.That(_grid.IsBlank(position), Is.False);
 }
 public void AllPositionsShouldBeBlankWhenANewGridIsCreated(Positions3X3 position)
 {
     Assert.That(_grid.IsBlank(position), Is.True);
 }
 public void AllPositionsShouldNotBeFilledWhenANewGridIsCreated(Positions3X3 position)
 {
     Assert.That(_grid.IsFilled(position), Is.False);
 }
 public void WhenIMarkAPosition_ItShouldNotBeFilled(Positions3X3 position)
 {
     _grid = Mark.Cross.On(_grid, position);
     Assert.That(_grid.IsFilled(position), Is.True);
 }