@Test
public void testMinInColumns() {

  final double[] expectedMinValues = new double[] {-1.00, 0, 0.50, -7.00};
  final int[] expectedMinIndices = new int[] {0, 0, 1, 2};
  final double[] actualMinValues = new double[4];
  final int[] actualMinColumnIndices =
      MatrixUtils.minInColumns(nonZeroColumnMatrix(), null, actualMinValues);
  assertThat(actualMinColumnIndices).isEqualTo(expectedMinIndices);
  assertThat(actualMinValues).isEqualTo(expectedMinValues);
}