public void Neighbors_GivenLocationWithEightCellsBordering_ReturnsEight() { // arrange for (int x = 0; x < 3; ++x) { for (int y = 0; y < 3; ++y) { universe.Add(x, y); } } // act int neighbors = universe.CountLivingNeighbors(1, 1); // assert Assert.AreEqual( expected: 8, actual: neighbors, message: "The cell did not have exactly 8 neighbors."); }