Testing custom Logstash filters

We are using Ansible and have Logstash.

How do I write a few tests to cover our custom logstash filters? What I want to do is this:

1. given a Logstash config with filters,
2. pass it a log line (or multiline log record),
3. see it successfully parsed into pieces.

I know there's this – http://ift.tt/1H7AW2M, but I don't understand how this is useful – it appears outdated.