chain.put("usersrepository", usersRepository);
dnsServer = new AlterableDNSServer();
chain.put("dnsservice", dnsServer);
store = new MockMailRepositoryStore();
chain.put("mailStore", store);
fileSystem = new MockFileSystem();
chain.put("fileSystem", fileSystem);
chain.put("org.apache.james.smtpserver.protocol.DNSService", dnsService);