@Test
    void requireThatValuesWorksAsExpected() {
        Headers headers = new Headers();
        assertTrue(headers.values().isEmpty());
        headers.add("foo", "bar");
        Collection<List<String>> values = headers.values();
        assertEquals(1, values.size());
        assertTrue(values.contains(List.of("bar")));

        headers.add("bar", "baz");
        values = headers.values();
        assertEquals(2, values.size());
        assertTrue(values.contains(List.of("bar")));
        assertTrue(values.contains(List.of("baz")));
    }
@author Simon Thoresen Hult
@author Einar M R Rosenvinge
application/src/test/java/com/yahoo/application/container/handler/HeadersTestCase.java