@Test
public void testSummary() {

  Table summary = column.summary();
  assertEquals(2, summary.columnCount());
  assertEquals(4, summary.rowCount());
  assertEquals("Count", summary.getUnformatted(0, 0));
  assertEquals("4", summary.getUnformatted(0, 1));
  assertEquals("Unique", summary.getUnformatted(1, 0));
  assertEquals("4", summary.getUnformatted(1, 1));
  assertEquals("Top", summary.getUnformatted(2, 0));
  assertEquals("Value 4", summary.getUnformatted(2, 1));
  assertEquals("Top Freq.", summary.getUnformatted(3, 0));
  assertEquals("1", summary.getUnformatted(3, 1));
}