Storing build runner data Follow

Hi,

I'm currently developping a plugin that adds a new test runner type. How can I store custom test data during the build process so that It can be displayed on one of the UI extension point (ideally TEST_DETAILS_BLOCK) after the build has completed ? Those tests are cloud ran and I need to store external ids and/or urls so users can see the full log on the external provider page.

Also, is there any other way to report unit testing live besides messages ?

Regards,
Bertrand