@Test
public void testToDoubleArray() {

  double[] result = column.asDoubleArray();
  assertEquals(0.0, result[0], 0.01);
  assertEquals(0.0, result[1], 0.01);
  assertEquals(0.0, result[2], 0.01);
  assertEquals(0.0, result[3], 0.01);
  assertEquals(1.0, result[4], 0.01);
  assertEquals(1.0, result[5], 0.01);
  assertEquals(0.0, result[6], 0.01);
}