test(recordings): Verify file contents from RecordingWorkflowIT

[jan-law]

Related #474

Addresses the TODOs in RecordingWorkflowIT:

// verify that reports can be downloaded successfully and yield non-empty HTML documents
// (TODO: verify response body is a valid HTML document)

// verify in-memory and saved recordings can be downloaded successfully and yield
// non-empty recording binaries (TODO: better verification of file content), and that
// the fully completed in-memory recording is larger than the saved partial copy

[jan-law]

What kinds of verification would be useful for the jfr files?

[andrewazores]

What kinds of verification would be useful for the jfr files?

JMC has a JFR file parser that we can probably use here - should be able to grab that through the -core dependency. I think checking that the JFR binary is parseable and that the resulting list of events is non-empty is probably enough. Also checking the byte-length of the binaries to do the "fully completed recording is larger than the saved partial copy" could be sufficient, although if there's already a JFR parser available then may as well use that to parse both and check that the parsed list of events is longer.

If you target Cryostat itself and use the Cryostat event template then I think you can guarantee that the recording should contain some events.

[jan-law]

if there's already a JFR parser available then may as well use that to parse both and check that the parsed list of events is longer

I found a JFR parser from jdk.jfr.consumer.RecordingFile that returns a list of events as I couldn't find the parser in -core.

[andrewazores]

if there's already a JFR parser available then may as well use that to parse both and check that the parsed list of events is longer

I found a JFR parser from jdk.jfr.consumer.RecordingFile that returns a list of events as I couldn't find the parser in -core.

Nice, that's even better.