pub fn strategy(platform: impl Strategy<Value = Platform>) -> impl Strategy<Value = Self> {
        prop_oneof![
            1 => Just(PlatformSpec::Any),
            1 => Just(PlatformSpec::Always),
            2 => platform.prop_map(PlatformSpec::from),
        ]
    }
Returns a [`Strategy`] that generates a random `PlatformSpec` instance.
guppy/src/platform/proptest_helpers.rs