@Test
    void requireThatAddStringWorksAsExpected() {
        Headers headers = new Headers();
        assertNull(headers.get("foo"));
        headers.add("foo", "bar");
        assertEquals(List.of("bar"), headers.get("foo"));
        headers.add("foo", "baz");
        assertEquals(List.of("bar", "baz"), headers.get("foo"));
    }
@author Simon Thoresen Hult
@author Einar M R Rosenvinge
application/src/test/java/com/yahoo/application/container/handler/HeadersTestCase.java