@Test
    @SuppressWarnings({"unchecked", "rawtypes"})
    void spliteratorCharacteristicsOfNullElement() {
        final SingletonStream containsNull = SingletonStream.of(null);
        final Spliterator<String> spliterator = containsNull.spliterator();
        assertEquals(0, spliterator.characteristics() & Spliterator.NONNULL);
    }
Test of mapToInt method, of class SingletonStream.
common-parent/singletonstream/src/test/java/com/speedment/common/singletonstream/SingletonStreamTest.java