(header ((h) ihello provides) ((sut) end_of_trail_action component) ((w) ihello requires))
(state ((h)) ((sut)) ((w)))
<external>.h.hello -> ...
... -> sut.h.hello
sut.w.hello -> ...
... -> <external>.w.hello
(state ((h)) ((sut)) ((w)))
(trail "h.hello" "w.hello")
(labels "h.hello" "w.cruel" "w.world")
(eligible "w.cruel" "w.world")
