@Test
public void test_null_lte_missing() {

  FunctionExpression lte = dsl.lte(DSL.ref(INT_TYPE_NULL_VALUE_FIELD, INTEGER),
      DSL.ref(INT_TYPE_MISSING_VALUE_FIELD, INTEGER));
  assertEquals(BOOLEAN, lte.type());
  assertEquals(LITERAL_MISSING, lte.valueOf(valueEnv()));
  lte = dsl.lte(DSL.ref(INT_TYPE_MISSING_VALUE_FIELD, INTEGER),
      DSL.ref(INT_TYPE_NULL_VALUE_FIELD, INTEGER));
  assertEquals(BOOLEAN, lte.type());
  assertEquals(LITERAL_MISSING, lte.valueOf(valueEnv()));
}