@Test
public void testGet() {

    DataFrame df = DataFrame.newFrame("a", "b").foldByRow(
            "a1", "b1",
            "a2", "b2");
    ByRowSeries s = new ByRowSeries(df);
    assertEquals("a1", s.get(0));
    assertEquals("b1", s.get(1));
    assertEquals("a2", s.get(2));
    assertEquals("b2", s.get(3));
}