@Test
    void requireThatEntriesAreUnmodifiable() {
        Headers headers = new Headers();
        headers.put("foo", "bar");
        List<Map.Entry<String, String>> entries = headers.entries();
        try {
            entries.add(new MyEntry());
            fail();
        } catch (UnsupportedOperationException e) {

        }
        try {
            entries.remove(new MyEntry());
            fail();
        } catch (UnsupportedOperationException e) {

        }
    }
@author Simon Thoresen Hult
@author Einar M R Rosenvinge
application/src/test/java/com/yahoo/application/container/handler/HeadersTestCase.java