Cargo Features

libgphoto2_sys has no features set by default.

libgphoto2_sys = { version = "1.2.2", features = ["test"] }
test = gphoto2_test

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

gphoto2_test test?