### Question:
Column implements WritableComparable<Column> { @Override public int compareTo(Column that) { return COMPARATOR.compare(this, that); } Column();  Column(byte[] columnFamily, byte[] columnQualifier, byte[] columnVisibility);  Column(TColumn tcol); @Override int compareTo(Column that); @Override void readFields(DataInput in); @Override void write(DataOutput out); @Override boolean equals(Object that); boolean equals(Column that); @Override int hashCode(); byte[] getColumnFamily(); byte[] getColumnQualifier(); byte[] getColumnVisibility(); @Override String toString(); TColumn toThrift(); public byte[] columnFamily; public byte[] columnQualifier; public byte[] columnVisibility; }### Answer:
@Test public void testCompare() { for (int i = 0; i < col.length; i++) { for (int j = 0; j < col.length; j++) { if (i == j || (i == 0 && j == 1) || (i == 1 && j == 0)) assertEquals(0, col[i].compareTo(col[j])); else assertNotEquals(0, col[i].compareTo(col[j])); } } }