@Override
    public Builder nullSafeEquals(String column, PredicateLeaf.Type type,
                                  Object literal) {
      ExpressionTree parent = currentTree.getFirst();
      if (column == null || literal == null) {
        parent.getChildren().add(new ExpressionTree(TruthValue.YES_NO_NULL));
      } else {
        PredicateLeafImpl leaf =
            new PredicateLeafImpl(PredicateLeaf.Operator.NULL_SAFE_EQUALS,
                type, column, literal, null, conf);
        parent.getChildren().add(new ExpressionTree(addLeaf(leaf)));
      }
      return this;
    }
Generate the backwards compatible string for test cases
@return the sarg using the old string
storage-api/src/java/org/apache/hadoop/hive/ql/io/sarg/SearchArgumentImpl.java