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));
}