public function testGetColumn()
{
$A = [[1, 2, 3], [2, 3, 4], [4, 5, 6]];
$matrix = MatrixFactory::create($A);
$this->assertEquals([1, 2, 4], $matrix->getColumn(0));
$this->assertEquals([2, 3, 5], $matrix->getColumn(1));
$this->assertEquals([3, 4, 6], $matrix->getColumn(2));
}