@Test
  public void testDeterminism() throws Exception {
    checkDeterministicFn(getUDF("+"));
    checkDeterministicFn(getUDF("ascii"));

    checkNondeterministicFn(getUDF("rand"));
    checkNondeterministicFn(getUDF("uuid"));

    checkRuntimeConstant(getUDF("current_database"));
    checkRuntimeConstant(getUDF("current_date"));
    checkRuntimeConstant(getUDF("current_timestamp"));
    checkRuntimeConstant(getUDF("current_user"));
    checkRuntimeConstant(getUDF("logged_in_user"));
  }
Method to print out the comparison/conversion behavior for data types.
ql/src/test/org/apache/hadoop/hive/ql/exec/TestFunctionRegistry.java