@Test
    void requireThatEntrySetWorksAsExpected() {
        Headers headers = new Headers();
        assertEquals(Set.of(), headers.entrySet());
        headers.put("foo", List.of("bar", "baz"));

        Set<Map.Entry<String, List<String>>> entries = headers.entrySet();
        assertEquals(1, entries.size());
        Map.Entry<String, List<String>> entry = entries.iterator().next();
        assertNotNull(entry);
        assertEquals("foo", entry.getKey());
        assertEquals(List.of("bar", "baz"), entry.getValue());
    }
@author Simon Thoresen Hult
@author Einar M R Rosenvinge
application/src/test/java/com/yahoo/application/container/handler/HeadersTestCase.java