def METHOD_NAME(self):
    # Test when the index is small enough to be within the upper, filled
    # grid.
    # This is the layout for displaying numbers from 0-9 with column
    # major setup:
    # 0  3  6  8
    # 1  4  7  9
    # 2  5  /  /
    # The index should be populated (row first) in this order:
    # 0, 3, 6, 8, 1, 4, 7, 9, 2, 5
    actual = column_major_to_row_major(
        index=6,
        n=10,
        num_rows=3,
        num_cols=4,
    )
    self.assertEqual(actual, 2)