void () { assertNull(JBIterable.<String>of().join(", ").reduce((a, b) -> a + b)); assertEquals("", JBIterable.of().join(", ").reduce("", (a, b) -> a + b)); assertEquals("a", JBIterable.of("a").join(", ").reduce((a, b) -> a + b)); assertEquals("a, b, c", JBIterable.of("a", "b", "c").join(", ").reduce((a, b) -> a + b)); }