Some of my rubygems – e.g. proxy_pac_rb – either need a backing HTTP(S)-server for their tests or interact with some external web services via HTTP/HTTPS. To mock external services you can either use VCR, webmock or just plain Webrick. To serve data for your tests via HTTP(S), you can use Webrick as well. As Webrick is part of ruby core and is sufficient for both use cases, this article only describes ways to run a Webrick-HTTP(S)-server to back your test suite.