### Question:
ColumnIndexOperandNode extends OperandNode { public int index() { return index; } ColumnIndexOperandNode(int index); int index(); @Override String toString();  }### Answer:
@Test public void testConstructor() { ColumnIndexOperandNode columnIndexOperandNode = new ColumnIndexOperandNode(5); assertEquals(5, columnIndexOperandNode.index()); assertNull(columnIndexOperandNode.getDataType()); }