public Protocol forName(final String identifier) {
        return this.forName(identifier, null);
    }
@Test
    public void testFindProtocolWithProviderInIdentifier() {
        final TestProtocol dav = new TestProtocol(Scheme.dav) {
            @Override
            public String getIdentifier() {
                return "dav";
            }

            @Override
            public String getProvider() {
                return "provider";
            }
        };
        final ProtocolFactory f = new ProtocolFactory(new LinkedHashSet<>(Collections.singletonList(dav)));
        assertEquals(dav, f.forName("dav"));
        assertEquals(dav, f.forName("dav-provider"));
    }