How to activate test mode

[b4nst]

As I understood, by default cue eval ignore every _test.cue files. When trying to specify a _test.cue file i get

_test.cue files excluded in non-test mode

Which made me wonder, is there a way to be in test mode?

[verdverm]

#209 #865

tl;dr cue test is planned but not implemented yet, _test.cue has been reserved in anticipation.