@Test
public void innerJoinStudentInstructorClassOnAge() {

  Table table1 = createSTUDENT();
  Table table2 = createINSTRUCTOR();
  Table table3 = createCLASS();
  Table joined = table1.joinOn("Age").inner(true, table2, table3);
  assert (joined
      .columnNames()
      .containsAll(
          Arrays.asList("T2.ID", "T2.City", "T2.State", "T2.USID", "T2.GradYear", "T3.ID")));
  assertEquals(24, joined.columnCount());
  assertEquals(14, joined.rowCount());
}