private String udfDisplayWithInputs() {
    return udf.getDisplayString(new String[] { value, pattern }) + " sessionZone=" + zone + ", formatter=" + formatter;
  }
Tests for {@link GenericUDFDateFormat#evaluate(DeferredObject[])} with string value inputs.
ql/src/test/org/apache/hadoop/hive/ql/udf/generic/TestGenericUDFDateFormatEvaluate.java