public void NeighborsThrowsExceptionIfIndexIsOutOfRange()
        {
            Int32[,] dblArray = new Int32[,] {
                {1, 2, 3},
                {2, 1, 2},
                {3, 2, 1}
            };

            var symmMatrix = new SymmetricMatrix<Int32>(Guid.NewGuid(), dblArray);
            Assert.Throws<AggregateException>(() => symmMatrix.Neighbors(4));
            Assert.Throws<ArgumentOutOfRangeException>(() => symmMatrix.Neighbors(-1));
        }