crates/camino/src/proptest_impls.rs

// Copyright (c) The camino Contributors
// SPDX-License-Identifier: MIT OR Apache-2.0

//! [proptest::Arbitrary](Arbitrary) implementation for `Utf8PathBuf` and `Box<Utf8Path>`.  Note
//! that implementions for `Rc<Utf8Path>` and `Arc<Utf8Path>` are not currently possible due to
//! orphan rules - this crate doesn't define `Rc`/`Arc` nor `Arbitrary`, so it can't define those
//! implementations.

// NOTE: #[cfg(feature = "proptest1")] is specified here to work with `doc_cfg`.

use crate::{Utf8Path, Utf8PathBuf};
use proptest::{arbitrary::StrategyFor, prelude::*, strategy::MapInto};

/// The [`Arbitrary`] impl for `Utf8PathBuf` returns a path with between 0 and 8 components,
/// joined by the [`MAIN_SEPARATOR`](std::path::MAIN_SEPARATOR) for the platform. (Each component is
/// randomly generated, and may itself contain one or more separators.)
///
/// On Unix, this generates an absolute path half of the time and a relative path the other half.
///
/// On Windows, this implementation doesn't currently generate
/// [`Utf8PrefixComponent`](crate::Utf8PrefixComponent) instances, though in the future it might.
#[cfg(feature = "proptest1")]
impl Arbitrary for Utf8PathBuf {
    type Parameters = <String as Arbitrary>::Parameters;
    type Strategy = BoxedStrategy<Self>;

    fn arbitrary_with(args: Self::Parameters) -> Self::Strategy {
        (
            any::<bool>(),
            prop::collection::vec(any_with::<String>(args), 0..8),
        )
            .prop_map(|(is_relative, components)| {
                let initial_component = if is_relative {
                    Some(format!("{}", std::path::MAIN_SEPARATOR))
                } else {
                    None
                };
                initial_component.into_iter().chain(components).collect()
            })
            .boxed()
    }
}

/// The [`Arbitrary`] impl for `Box<Utf8Path>` returns a path with between 0 and 8 components,
/// joined by the [`MAIN_SEPARATOR`](std::path::MAIN_SEPARATOR) for the platform. (Each component is
/// randomly generated, and may itself contain one or more separators.)
///
/// On Unix, this generates an absolute path half of the time and a relative path the other half.
///
/// On Windows, this implementation doesn't currently generate
/// [`Utf8PrefixComponent`](crate::Utf8PrefixComponent) instances, though in the future it might.
#[cfg(feature = "proptest1")]
impl Arbitrary for Box<Utf8Path> {
    type Parameters = <Utf8PathBuf as Arbitrary>::Parameters;
    type Strategy = MapInto<StrategyFor<Utf8PathBuf>, Self>;

    fn arbitrary_with(args: Self::Parameters) -> Self::Strategy {
        any_with::<Utf8PathBuf>(args).prop_map_into()
    }
}