Turning on --all-features compiled every translation backend, so the test
asserting that a known-but-uncompiled engine is refused had nothing left to
refuse and failed. It hardcoded "deepl" and a comment that no feature was
on, which stopped being true in the same commit that made CI see it.
It now picks whichever engine this build did not compile, and when all of
them are compiled asserts the complementary truth instead: a compiled
engine is accepted. Meaningful under either feature set.
Miguel Palhas