### Question:
ServerState implements Iterable<CSN> { public boolean cover(ServerState covered) { for (CSN coveredChange : covered.serverIdToCSN.values()) { if (!cover(coveredChange)) { return false; } } return true; } ServerState(); void clear(); boolean update(CSN csn); boolean update(ServerState serverState); boolean removeCSN(CSN expectedCSN); boolean reload(ServerState serverState); Set<String> toStringSet(); ArrayList<ByteString> toASN1ArrayList(); void writeTo(ASN1Writer writer, short protocolVersion); List<CSN> getSnapshot(); @Override String toString(); CSN getCSN(int serverId); Map<Integer, CSN> getServerIdToCSNMap(); @Override Iterator<CSN> iterator(); boolean cover(ServerState covered); boolean cover(CSN covered); boolean isEmpty(); ServerState duplicate(); static int diffChanges(ServerState ss1, ServerState ss2); void setSaved(boolean b); boolean isSaved();  }### Answer:
@Test public void testCover() throws Exception { final CSN csn1Server1 = new CSN(1, 0, 1); final CSN csn2Server1 = new CSN(2, 0, 1); final CSN csn1Server2 = new CSN(1, 0, 2); final CSN csn0Server3 = new CSN(0, 0, 3); final ServerState state = new ServerState(); assertFalse(state.cover(csn1Server1)); assertFalse(state.cover(csn2Server1)); assertFalse(state.cover(csn1Server2)); assertFalse(state.cover(csn0Server3)); state.update(csn1Server1); assertTrue(state.cover(csn1Server1)); assertFalse(state.cover(csn2Server1)); assertFalse(state.cover(csn1Server2)); assertFalse(state.cover(csn0Server3)); state.update(csn1Server2); assertTrue(state.cover(csn1Server1)); assertFalse(state.cover(csn2Server1)); assertTrue(state.cover(csn1Server2)); assertFalse(state.cover(csn0Server3)); state.update(csn2Server1); assertTrue(state.cover(csn1Server1)); assertTrue(state.cover(csn2Server1)); assertTrue(state.cover(csn1Server2)); assertFalse(state.cover(csn0Server3)); }