@Test
    void testOfNullableNull() {
        final Stream<String> ss = SingletonStream.ofNullable(null);
        final List<String> s = ss.collect(toList());
        assertEquals(Collections.emptyList(), s);
    }
Test of ofNullable method, of class SingletonStream.
common-parent/singletonstream/src/test/java/com/speedment/common/singletonstream/SingletonStreamTest.java