More testing

[simonsan]

We should have better testing here.

Some e2e testing we can do with hurl, where we can write HTTP requests and assert on the responses.

Otherwise, we need to collect some targets for unit testing.

[simonsan]

• Hurl support came with 42cf95a, although it needs some improvements
• the tests have been fixed in 42cf95a as well and are quite extensive already, but we probably want some more