@Test
  public void testToStringWithNonNullComparator() {
    Filter filter = new DependentColumnFilter(FAMILIES[0], QUALIFIER, true, CompareOperator.EQUAL,
      new BinaryComparator(MATCH_VAL));
    assertNotNull(filter.toString());
    assertTrue("check string contains comparator value", filter.toString().contains("match"));
  }
Test for HBASE-8794. Avoid NullPointerException in DependentColumnFilter.toString().
hbase-server/src/test/java/org/apache/hadoop/hbase/filter/TestDependentColumnFilter.java