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Diffstat (limited to 'vendor/proptest/src/arbitrary/functor.rs')
| -rw-r--r-- | vendor/proptest/src/arbitrary/functor.rs | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/vendor/proptest/src/arbitrary/functor.rs b/vendor/proptest/src/arbitrary/functor.rs new file mode 100644 index 000000000..153ce9949 --- /dev/null +++ b/vendor/proptest/src/arbitrary/functor.rs @@ -0,0 +1,220 @@ +//- +// Copyright 2017, 2018 The proptest developers +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! Provides higher order `Arbitrary` traits. +//! This is mainly for use by `proptest_derive`. +//! +//! ## Stability note +//! +//! This trait is mainly defined for `proptest_derive` to simplify the +//! mechanics of deriving recursive types. If you have custom containers +//! and want to support recursive for those, it is a good idea to implement +//! this trait. +//! +//! There are clearer and terser ways that work better with +//! inference such as using `proptest::collection::vec(..)` +//! to achieve the same result. +//! +//! For these reasons, the traits here are deliberately +//! not exported in a convenient way. + +use crate::std_facade::fmt; + +use crate::strategy::{BoxedStrategy, Strategy}; + +/// `ArbitraryF1` lets you lift a [`Strategy`] to unary +/// type constructors such as `Box`, `Vec`, and `Option`. +/// +/// The trait corresponds to +/// [Haskell QuickCheck's `Arbitrary1` type class][HaskellQC]. +/// +/// [HaskellQC]: +/// https://hackage.haskell.org/package/QuickCheck-2.10.1/docs/Test-QuickCheck-Arbitrary.html#t:Arbitrary1 +/// +/// [`Strategy`]: ../proptest/strategy/trait.Strategy.html +pub trait ArbitraryF1<A: fmt::Debug>: fmt::Debug + Sized { + //========================================================================== + // Implementation note #1 + //========================================================================== + // It might be better to do this with generic associated types by + // having an associated type: + // + // `type Strategy<A>: Strategy<Value = Self>;` + // + // But with this setup we will likely loose the ability to add bounds + // such as `Hash + Eq` on `A` which is needed for `HashSet`. We might + // be able to regain this ability with a ConstraintKinds feature. + // + // This alternate formulation will likely work better with type inference. + // + //========================================================================== + // Implementation note #2 + //========================================================================== + // + // Until `-> impl Trait` has been stabilized, `BoxedStrategy` must be + // used. This incurs an unfortunate performance penalty - but since + // we are dealing with testing, it is better to provide slowed down and + // somewhat less general functionality than no functionality at all. + // Implementations should just use `.boxed()` in the end. + //========================================================================== + + /// The type of parameters that [`lift1_with`] accepts for + /// configuration of the lifted and generated [`Strategy`]. Parameters + /// must implement [`Default`]. + /// + /// [`lift1_with`]: + /// trait.ArbitraryF1.html#tymethod.lift1_with + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// [`Default`]: + /// https://doc.rust-lang.org/nightly/std/default/trait.Default.html + type Parameters: Default; + + /// Lifts a given [`Strategy`] to a new [`Strategy`] for the (presumably) + /// bigger type. This is useful for lifting a `Strategy` for `SomeType` + /// to a container such as `Vec<SomeType>`. + /// + /// Calling this for the type `X` is the equivalent of using + /// [`X::lift1_with(base, Default::default())`]. + /// + /// This method is defined in the trait for optimization for the + /// default if you want to do that. It is a logic error to not + /// preserve the semantics when overriding. + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// + /// [`X::lift1_with(base, Default::default())`]: + /// trait.ArbitraryF1.html#tymethod.lift1_with + fn lift1<AS>(base: AS) -> BoxedStrategy<Self> + where + AS: Strategy<Value = A> + 'static, + { + Self::lift1_with(base, Self::Parameters::default()) + } + + /// Lifts a given [`Strategy`] to a new [`Strategy`] for the (presumably) + /// bigger type. This is useful for lifting a `Strategy` for `SomeType` + /// to a container such as `Vec` of `SomeType`. The composite strategy is + /// passed the arguments given in `args`. + /// + /// If you wish to use the [`default()`] arguments, + /// use [`lift1`] instead. + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// + /// [`lift1`]: trait.ArbitraryF1.html#method.lift1 + /// + /// [`default()`]: + /// https://doc.rust-lang.org/nightly/std/default/trait.Default.html + fn lift1_with<AS>(base: AS, args: Self::Parameters) -> BoxedStrategy<Self> + where + AS: Strategy<Value = A> + 'static; +} + +/// `ArbitraryF2` lets you lift [`Strategy`] to binary +/// type constructors such as `Result`, `HashMap`. +/// +/// The trait corresponds to +/// [Haskell QuickCheck's `Arbitrary2` type class][HaskellQC]. +/// +/// [HaskellQC]: +/// https://hackage.haskell.org/package/QuickCheck-2.10.1/docs/Test-QuickCheck-Arbitrary.html#t:Arbitrary2 +/// +/// [`Strategy`]: ../proptest/strategy/trait.Strategy.html +pub trait ArbitraryF2<A: fmt::Debug, B: fmt::Debug>: + fmt::Debug + Sized +{ + /// The type of parameters that [`lift2_with`] accepts for + /// configuration of the lifted and generated [`Strategy`]. Parameters + /// must implement [`Default`]. + /// + /// [`lift2_with`]: trait.ArbitraryF2.html#tymethod.lift2_with + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// + /// [`Default`]: + /// https://doc.rust-lang.org/nightly/std/default/trait.Default.html + type Parameters: Default; + + /// Lifts two given strategies to a new [`Strategy`] for the (presumably) + /// bigger type. This is useful for lifting a `Strategy` for `Type1` + /// and one for `Type2` to a container such as `HashMap<Type1, Type2>`. + /// + /// Calling this for the type `X` is the equivalent of using + /// [`X::lift2_with(base, Default::default())`]. + /// + /// This method is defined in the trait for optimization for the + /// default if you want to do that. It is a logic error to not + /// preserve the semantics when overriding. + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// + /// [`X::lift2_with(base, Default::default())`]: + /// trait.Arbitrary.html#tymethod.lift2_with + fn lift2<AS, BS>(fst: AS, snd: BS) -> BoxedStrategy<Self> + where + AS: Strategy<Value = A> + 'static, + BS: Strategy<Value = B> + 'static, + { + Self::lift2_with(fst, snd, Self::Parameters::default()) + } + + /// Lifts two given strategies to a new [`Strategy`] for the (presumably) + /// bigger type. This is useful for lifting a `Strategy` for `Type1` + /// and one for `Type2` to a container such as `HashMap<Type1, Type2>`. + /// The composite strategy is passed the arguments given in `args`. + /// + /// If you wish to use the [`default()`] arguments, + /// use [`lift2`] instead. + /// + /// [`Strategy`]: ../proptest/strategy/trait.Strategy.html + /// + /// [`lift2`]: trait.ArbitraryF2.html#method.lift2 + /// + /// [`default()`]: + /// https://doc.rust-lang.org/nightly/std/default/trait.Default.html + fn lift2_with<AS, BS>( + fst: AS, + snd: BS, + args: Self::Parameters, + ) -> BoxedStrategy<Self> + where + AS: Strategy<Value = A> + 'static, + BS: Strategy<Value = B> + 'static; +} + +macro_rules! lift1 { + ([$($bounds : tt)*] $typ: ty, $params: ty; + $base: ident, $args: ident => $logic: expr) => { + impl<A: ::core::fmt::Debug + $($bounds)*> + $crate::arbitrary::functor::ArbitraryF1<A> + for $typ { + type Parameters = $params; + + fn lift1_with<S>($base: S, $args: Self::Parameters) + -> $crate::strategy::BoxedStrategy<Self> + where + S: $crate::strategy::Strategy<Value = A> + 'static + { + $crate::strategy::Strategy::boxed($logic) + } + } + }; + ([$($bounds : tt)*] $typ: ty; $base: ident => $logic: expr) => { + lift1!([$($bounds)*] $typ, (); $base, _args => $logic); + }; + ([$($bounds : tt)*] $typ: ty; $mapper: expr) => { + lift1!(['static + $($bounds)*] $typ; base => + $crate::strategy::Strategy::prop_map(base, $mapper)); + }; + ([$($bounds : tt)*] $typ: ty) => { + lift1!(['static + $($bounds)*] $typ; base => + $crate::strategy::Strategy::prop_map_into(base)); + }; +} |