soroban_sdk/testutils/

arbitrary.rs

//! Support for fuzzing Soroban contracts with [`cargo-fuzz`].
//!
//! This module provides a pattern for generating Soroban contract types for the
//! purpose of fuzzing Soroban contracts. It is focused on implementing the
//! [`Arbitrary`] trait that `cargo-fuzz` relies on to feed fuzzers with
//! generated Rust values.
//!
//! [`cargo-fuzz`]: https://github.com/rust-fuzz/cargo-fuzz/
//! [`Arbitrary`]: ::arbitrary::Arbitrary
//!
//! This module
//!
//! - defines the [`SorobanArbitrary`] trait,
//! - reexports the [`arbitrary`] crate and the [`Arbitrary`] type.
//!
//! This module is only available when the "testutils" Cargo feature is defined.
//!
//!
//! ## About `cargo-fuzz` and `Arbitrary`
//!
//! In its basic operation `cargo-fuzz` fuzz generates raw bytes and feeds them
//! to a program-dependent fuzzer designed to exercise a program, in our case a
//! Soroban contract.
//!
//! `cargo-fuzz` programs declare their entry points with a macro:
//!
//! ```
//! # macro_rules! fuzz_target {
//! #     (|$data:ident: $dty: ty| $body:block) => { };
//! # }
//! fuzz_target!(|input: &[u8]| {
//!     // feed bytes to the program
//! });
//! ```
//!
//! More sophisticated fuzzers accept not bytes but Rust types:
//!
//! ```
//! # use arbitrary::Arbitrary;
//! # macro_rules! fuzz_target {
//! #     (|$data:ident: $dty: ty| $body:block) => { };
//! # }
//! #[derive(Arbitrary, Debug)]
//! struct FuzzDeposit {
//!     deposit_amount: i128,
//! }
//!
//! fuzz_target!(|input: FuzzDeposit| {
//!     // fuzz the program based on the input
//! });
//! ```
//!
//! Types accepted as input to `fuzz_target` must implement the `Arbitrary` trait,
//! which transforms bytes to Rust types.
//!
//!
//! ## The `SorobanArbitrary` trait
//!
//! Soroban types are managed by the host environment, and so must be created
//! from an [`Env`] value; `Arbitrary` values though must be created from
//! nothing but bytes. The [`SorobanArbitrary`] trait, implemented for all
//! Soroban contract types, exists to bridge this gap: it defines a _prototype_
//! pattern whereby the `fuzz_target` macro creates prototype values that the
//! fuzz program can convert to contract values with the standard soroban
//! conversion traits, [`FromVal`] or [`IntoVal`].
//!
//! [`Env`]: crate::Env
//! [`FromVal`]: crate::FromVal
//! [`IntoVal`]: crate::IntoVal
//!
//! The types of prototypes are identified by the associated type,
//! [`SorobanArbitrary::Prototype`]:
//!
//! ```
//! # use soroban_sdk::testutils::arbitrary::Arbitrary;
//! # use soroban_sdk::{TryFromVal, IntoVal, Val, Env};
//! pub trait SorobanArbitrary:
//!     TryFromVal<Env, Self::Prototype> + IntoVal<Env, Val> + TryFromVal<Env, Val>
//! {
//!     type Prototype: for <'a> Arbitrary<'a>;
//! }
//! ```
//!
//! Types that implement `SorobanArbitrary` include:
//!
//! - `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `I256`, `U256`, `()`, and `bool`,
//! - [`Error`],
//! - [`Bytes`], [`BytesN`], [`Vec`], [`Map`],
//! - [`Address`], [`Symbol`],
//! - [`Val`],
//!
//! [`I256`]: crate::I256
//! [`U256`]: crate::U256
//! [`Error`]: crate::Error
//! [`Bytes`]: crate::Bytes
//! [`BytesN`]: crate::BytesN
//! [`Vec`]: crate::Vec
//! [`Map`]: crate::Map
//! [`Address`]: crate::Address
//! [`Symbol`]: crate::Symbol
//! [`Val`]: crate::Val
//!
//! All user-defined contract types, those with the [`contracttype`] attribute,
//! automatically derive `SorobanArbitrary`. Note that `SorobanArbitrary` is
//! only derived when the "testutils" Cargo feature is active. This implies
//! that, in general, to make a Soroban contract fuzzable, the contract crate
//! must define a "testutils" Cargo feature, that feature should turn on the
//! "soroban-sdk/testutils" feature, and the fuzz test, which is its own crate,
//! must turn that feature on.
//!
//! [`contracttype`]: crate::contracttype
//!
//!
//! ## Example: take a Soroban `Vec` of `Address` as fuzzer input
//!
//! ```
//! # macro_rules! fuzz_target {
//! #     (|$data:ident: $dty: ty| $body:block) => { };
//! # }
//! use soroban_sdk::{Address, Env, Vec};
//! use soroban_sdk::testutils::arbitrary::SorobanArbitrary;
//!
//! fuzz_target!(|input: <Vec<Address> as SorobanArbitrary>::Prototype| {
//!     let env = Env::default();
//!     let addresses: Vec<Address> = input.into_val(&env);
//!     // fuzz the program based on the input
//! });
//! ```
//!
//!
//! ## Example: take a custom contract type as fuzzer input
//!
//! ```
//! # macro_rules! fuzz_target {
//! #     (|$data:ident: $dty: ty| $body:block) => { };
//! # }
//! use soroban_sdk::{Address, Env, Vec};
//! use soroban_sdk::contracttype;
//! use soroban_sdk::testutils::arbitrary::{Arbitrary, SorobanArbitrary};
//! use std::vec::Vec as RustVec;
//!
//! #[derive(Arbitrary, Debug)]
//! struct TestInput {
//!     deposit_amount: i128,
//!     claim_address: <Address as SorobanArbitrary>::Prototype,
//!     time_bound: <TimeBound as SorobanArbitrary>::Prototype,
//! }
//!
//! #[contracttype]
//! pub struct TimeBound {
//!     pub kind: TimeBoundKind,
//!     pub timestamp: u64,
//! }
//!
//! #[contracttype]
//! pub enum TimeBoundKind {
//!     Before,
//!     After,
//! }
//!
//! fuzz_target!(|input: TestInput| {
//!     let env = Env::default();
//!     let claim_address: Address = input.claim_address.into_val(&env);
//!     let time_bound: TimeBound = input.time_bound.into_val(&env);
//!     // fuzz the program based on the input
//! });
//! ```

/// A reexport of the `arbitrary` crate.
///
/// Used by the `contracttype` macro to derive `Arbitrary`.
pub use arbitrary;

// Used often enough in fuzz tests to want direct access to it.
pub use arbitrary::Arbitrary;

// Used by `contracttype`
#[doc(hidden)]
pub use std;

pub use api::*;
pub use fuzz_test_helpers::*;

/// The traits that must be implemented on Soroban types to support fuzzing.
///
/// These allow for ergonomic conversion from a randomly-generated "prototype"
/// that implements `Arbitrary` into `Env`-"hosted" values that are paired with an
/// `Env`.
///
/// These traits are intended to be easy to automatically derive.
mod api {
    use crate::Env;
    use crate::Val;
    use crate::{IntoVal, TryFromVal};
    use arbitrary::Arbitrary;

    /// An `Env`-hosted contract value that can be randomly generated.
    ///
    /// Types that implement `SorabanArbitrary` have an associated "prototype"
    /// type that implements [`Arbitrary`].
    ///
    /// This exists partly so that the prototype can be named like
    ///
    /// ```
    /// # macro_rules! fuzz_target {
    /// #     (|$data:ident: $dty: ty| $body:block) => { };
    /// # }
    /// # use soroban_sdk::{Address, Env, Vec, Bytes};
    /// # use soroban_sdk::testutils::arbitrary::SorobanArbitrary;
    /// fuzz_target!(|input: <Bytes as SorobanArbitrary>::Prototype| {
    ///     // ...
    /// });
    /// ```
    // This also makes derivation of `SorobanArbitrary` for custom types easier
    // since we depend on all fields also implementing `SorobanArbitrary`.
    //
    // The IntoVal<Env, Val> + TryFromVal<Env, Val> bounds are to satisfy
    // the bounds of Vec and Map, so that collections of prototypes can be
    // converted to contract types.
    pub trait SorobanArbitrary:
        TryFromVal<Env, Self::Prototype> + IntoVal<Env, Val> + TryFromVal<Env, Val>
    {
        /// A type that implements [`Arbitrary`] and can be converted to this
        /// [`SorobanArbitrary`] type.
        // NB: The `Arbitrary` bound here is not necessary for the correct use of
        // `SorobanArbitrary`, but it makes the purpose clear.
        type Prototype: for<'a> Arbitrary<'a>;
    }
}

/// Implementations of `soroban_sdk::testutils::arbitrary::api` for Rust scalar types.
///
/// These types
///
/// - do not have a distinct `Arbitrary` prototype,
///   i.e. they use themselves as the `SorobanArbitrary::Prototype` type,
/// - implement `Arbitrary` in the `arbitrary` crate,
/// - trivially implement `TryFromVal<Env, SorobanArbitrary::Prototype>`,
///
/// Examples:
///
/// - `u32`
mod scalars {
    use super::api::*;

    impl SorobanArbitrary for () {
        type Prototype = ();
    }

    impl SorobanArbitrary for bool {
        type Prototype = bool;
    }

    impl SorobanArbitrary for u32 {
        type Prototype = u32;
    }

    impl SorobanArbitrary for i32 {
        type Prototype = i32;
    }

    impl SorobanArbitrary for u64 {
        type Prototype = u64;
    }

    impl SorobanArbitrary for i64 {
        type Prototype = i64;
    }

    impl SorobanArbitrary for u128 {
        type Prototype = u128;
    }

    impl SorobanArbitrary for i128 {
        type Prototype = i128;
    }
}

/// Implementations of `soroban_sdk::testutils::arbitrary::api` for Soroban types that do not
/// need access to the Soroban host environment.
///
/// These types
///
/// - do not have a distinct `Arbitrary` prototype,
///   i.e. they use themselves as the `SorobanArbitrary::Prototype` type,
/// - implement `Arbitrary` in the `soroban-env-common` crate,
/// - trivially implement `TryFromVal<Env, SorobanArbitrary::Prototype>`,
///
/// Examples:
///
/// - `Error`
mod simple {
    use super::api::*;
    pub use crate::Error;

    impl SorobanArbitrary for Error {
        type Prototype = Error;
    }
}

/// Implementations of `soroban_sdk::testutils::arbitrary::api` for Soroban types that do
/// need access to the Soroban host environment.
///
/// These types
///
/// - have a distinct `Arbitrary` prototype that derives `Arbitrary`,
/// - require an `Env` to be converted to their actual contract type.
///
/// Examples:
///
/// - `Vec`
mod objects {
    use arbitrary::{Arbitrary, Result as ArbitraryResult, Unstructured};

    use super::api::*;
    use super::composite::ArbitraryVal;
    use crate::env::FromVal;
    use crate::ConversionError;
    use crate::{Env, IntoVal, TryFromVal, TryIntoVal};

    use crate::xdr::{Int256Parts, ScVal, UInt256Parts};
    use crate::{
        Address, Bytes, BytesN, Duration, Map, String, Symbol, Timepoint, Val, Vec, I256, U256,
    };

    use std::string::String as RustString;
    use std::vec::Vec as RustVec;

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryOption<T>(Option<T>);

    impl<T> SorobanArbitrary for Option<T>
    where
        T: SorobanArbitrary,
        Val: TryFromVal<Env, T>,
    {
        type Prototype = ArbitraryOption<T::Prototype>;
    }

    impl<T> TryFromVal<Env, ArbitraryOption<T::Prototype>> for Option<T>
    where
        T: SorobanArbitrary,
    {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryOption<T::Prototype>) -> Result<Self, Self::Error> {
            match v.0 {
                Some(ref t) => Ok(Some(t.into_val(env))),
                None => Ok(None),
            }
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryU256 {
        parts: (u64, u64, u64, u64),
    }

    impl SorobanArbitrary for U256 {
        type Prototype = ArbitraryU256;
    }

    impl TryFromVal<Env, ArbitraryU256> for U256 {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryU256) -> Result<Self, Self::Error> {
            let v = ScVal::U256(UInt256Parts {
                hi_hi: v.parts.0,
                hi_lo: v.parts.1,
                lo_hi: v.parts.2,
                lo_lo: v.parts.3,
            });
            let v = Val::try_from_val(env, &v)?;
            v.try_into_val(env)
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryI256 {
        parts: (i64, u64, u64, u64),
    }

    impl SorobanArbitrary for I256 {
        type Prototype = ArbitraryI256;
    }

    impl TryFromVal<Env, ArbitraryI256> for I256 {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryI256) -> Result<Self, Self::Error> {
            let v = ScVal::I256(Int256Parts {
                hi_hi: v.parts.0,
                hi_lo: v.parts.1,
                lo_hi: v.parts.2,
                lo_lo: v.parts.3,
            });
            let v = Val::try_from_val(env, &v)?;
            v.try_into_val(env)
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryBytes {
        vec: RustVec<u8>,
    }

    impl SorobanArbitrary for Bytes {
        type Prototype = ArbitraryBytes;
    }

    impl TryFromVal<Env, ArbitraryBytes> for Bytes {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryBytes) -> Result<Self, Self::Error> {
            Self::try_from_val(env, &v.vec.as_slice())
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryString {
        inner: RustString,
    }

    impl SorobanArbitrary for String {
        type Prototype = ArbitraryString;
    }

    impl TryFromVal<Env, ArbitraryString> for String {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryString) -> Result<Self, Self::Error> {
            Self::try_from_val(env, &v.inner.as_str())
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryBytesN<const N: usize> {
        array: [u8; N],
    }

    impl<const N: usize> SorobanArbitrary for BytesN<N> {
        type Prototype = ArbitraryBytesN<N>;
    }

    impl<const N: usize> TryFromVal<Env, ArbitraryBytesN<N>> for BytesN<N> {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryBytesN<N>) -> Result<Self, Self::Error> {
            Self::try_from_val(env, &v.array)
        }
    }

    //////////////////////////////////

    #[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitrarySymbol {
        s: RustString,
    }

    impl<'a> Arbitrary<'a> for ArbitrarySymbol {
        fn arbitrary(u: &mut Unstructured<'a>) -> ArbitraryResult<ArbitrarySymbol> {
            let valid_chars = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            let valid_chars = valid_chars.as_bytes();
            let mut chars = vec![];
            let len = u.int_in_range(0..=32)?;
            for _ in 0..len {
                let ch = u.choose(valid_chars)?;
                chars.push(*ch);
            }
            Ok(ArbitrarySymbol {
                s: RustString::from_utf8(chars).expect("utf8"),
            })
        }
    }

    impl SorobanArbitrary for Symbol {
        type Prototype = ArbitrarySymbol;
    }

    impl TryFromVal<Env, ArbitrarySymbol> for Symbol {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitrarySymbol) -> Result<Self, Self::Error> {
            Self::try_from_val(env, &v.s.as_str())
        }
    }

    //////////////////////////////////

    #[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryVec<T> {
        Good(RustVec<T>),
        // Vec<T> can be constructed with non-T values.
        Wrong(RustVec<ArbitraryVal>),
    }

    impl<'a, T> Arbitrary<'a> for ArbitraryVec<T>
    where
        T: Arbitrary<'a>,
    {
        fn arbitrary(u: &mut Unstructured<'a>) -> ArbitraryResult<ArbitraryVec<T>> {
            // How frequently we provide ArbitraryVec::Wrong
            const WRONG_TYPE_RATIO: (u16, u16) = (1, 1000);

            if u.ratio(WRONG_TYPE_RATIO.0, WRONG_TYPE_RATIO.1)? {
                Ok(ArbitraryVec::Wrong(Arbitrary::arbitrary(u)?))
            } else {
                Ok(ArbitraryVec::Good(Arbitrary::arbitrary(u)?))
            }
        }
    }

    impl<T> SorobanArbitrary for Vec<T>
    where
        T: SorobanArbitrary,
    {
        type Prototype = ArbitraryVec<T::Prototype>;
    }

    impl<T> TryFromVal<Env, ArbitraryVec<T::Prototype>> for Vec<T>
    where
        T: SorobanArbitrary,
    {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryVec<T::Prototype>) -> Result<Self, Self::Error> {
            match v {
                ArbitraryVec::Good(vec) => {
                    let mut buf: Vec<T> = Vec::new(env);
                    for item in vec.iter() {
                        buf.push_back(item.into_val(env));
                    }
                    Ok(buf)
                }
                ArbitraryVec::Wrong(vec) => {
                    let mut buf: Vec<Val> = Vec::new(env);
                    for item in vec.iter() {
                        buf.push_back(item.into_val(env));
                    }
                    Ok(Vec::<T>::from_val(env, &buf.to_val()))
                }
            }
        }
    }

    //////////////////////////////////

    #[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryMap<K, V> {
        Good(RustVec<(K, V)>),
        // Maps can be constructed with non-T K/Vs
        WrongKey(RustVec<(ArbitraryVal, V)>),
        WrongValue(RustVec<(K, ArbitraryVal)>),
    }

    impl<'a, K, V> Arbitrary<'a> for ArbitraryMap<K, V>
    where
        K: Arbitrary<'a>,
        V: Arbitrary<'a>,
    {
        fn arbitrary(u: &mut Unstructured<'a>) -> ArbitraryResult<ArbitraryMap<K, V>> {
            // How frequently we provide ArbitraryMap::Wrong*
            const WRONG_TYPE_RATIO: (u16, u16) = (1, 1000);

            if u.ratio(WRONG_TYPE_RATIO.0, WRONG_TYPE_RATIO.1)? {
                if u.arbitrary::<bool>()? {
                    Ok(ArbitraryMap::WrongKey(Arbitrary::arbitrary(u)?))
                } else {
                    Ok(ArbitraryMap::WrongValue(Arbitrary::arbitrary(u)?))
                }
            } else {
                Ok(ArbitraryMap::Good(Arbitrary::arbitrary(u)?))
            }
        }
    }

    impl<K, V> SorobanArbitrary for Map<K, V>
    where
        K: SorobanArbitrary,
        V: SorobanArbitrary,
    {
        type Prototype = ArbitraryMap<K::Prototype, V::Prototype>;
    }

    impl<K, V> TryFromVal<Env, ArbitraryMap<K::Prototype, V::Prototype>> for Map<K, V>
    where
        K: SorobanArbitrary,
        V: SorobanArbitrary,
    {
        type Error = ConversionError;
        fn try_from_val(
            env: &Env,
            v: &ArbitraryMap<K::Prototype, V::Prototype>,
        ) -> Result<Self, Self::Error> {
            match v {
                ArbitraryMap::Good(vec) => {
                    let mut map: Map<K, V> = Map::new(env);
                    for (k, v) in vec.iter() {
                        map.set(k.into_val(env), v.into_val(env));
                    }
                    Ok(map)
                }
                ArbitraryMap::WrongKey(vec) => {
                    let mut map: Map<Val, V> = Map::new(env);
                    for (k, v) in vec.iter() {
                        map.set(k.into_val(env), v.into_val(env));
                    }
                    Ok(Map::<K, V>::from_val(env, &map.to_val()))
                }
                ArbitraryMap::WrongValue(vec) => {
                    let mut map: Map<K, Val> = Map::new(env);
                    for (k, v) in vec.iter() {
                        map.set(k.into_val(env), v.into_val(env));
                    }
                    Ok(Map::<K, V>::from_val(env, &map.to_val()))
                }
            }
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryAddress {
        inner: [u8; 32],
    }

    impl SorobanArbitrary for Address {
        type Prototype = ArbitraryAddress;
    }

    impl TryFromVal<Env, ArbitraryAddress> for Address {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryAddress) -> Result<Self, Self::Error> {
            use crate::env::xdr::{Hash, ScAddress};

            let sc_addr = ScVal::Address(ScAddress::Contract(Hash(v.inner)));
            Ok(sc_addr.into_val(env))
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryTimepoint {
        inner: u64,
    }

    impl SorobanArbitrary for Timepoint {
        type Prototype = ArbitraryTimepoint;
    }

    impl TryFromVal<Env, ArbitraryTimepoint> for Timepoint {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryTimepoint) -> Result<Self, Self::Error> {
            let sc_timepoint = ScVal::Timepoint(crate::xdr::TimePoint::from(v.inner));
            Ok(sc_timepoint.into_val(env))
        }
    }

    //////////////////////////////////

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub struct ArbitraryDuration {
        inner: u64,
    }

    impl SorobanArbitrary for Duration {
        type Prototype = ArbitraryDuration;
    }

    impl TryFromVal<Env, ArbitraryDuration> for Duration {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryDuration) -> Result<Self, Self::Error> {
            let sc_duration = ScVal::Duration(crate::xdr::Duration::from(v.inner));
            Ok(sc_duration.into_val(env))
        }
    }
}

/// Implementations of `soroban_sdk::testutils::arbitrary::api` for tuples of Soroban types.
///
/// The implementation is similar to objects, but macroized.
mod tuples {
    use super::api::*;
    use crate::ConversionError;
    use crate::{Env, IntoVal, TryFromVal, TryIntoVal, Val};
    use arbitrary::Arbitrary;

    macro_rules! impl_tuple {
        ($name: ident, $($ty: ident),+ ) => {
            #[allow(non_snake_case)] // naming fields T1, etc.
            #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
            pub struct $name<$($ty,)*> {
                $($ty: $ty,)*
            }

            impl<$($ty,)*> SorobanArbitrary for ($($ty,)*)
            where $($ty: SorobanArbitrary + TryIntoVal<Env, Val>,)*
            {
                type Prototype = $name<$($ty::Prototype,)*>;
            }

            impl<$($ty,)*> TryFromVal<Env, $name<$($ty::Prototype,)*>> for ($($ty,)*)
            where $($ty: SorobanArbitrary,)*
            {
                type Error = ConversionError;
                fn try_from_val(env: &Env, v: &$name<$($ty::Prototype,)*>) -> Result<Self, Self::Error> {
                    Ok(($(
                        v.$ty.into_val(env),
                    )*))
                }
            }
        }
    }

    impl_tuple!(ArbitraryTuple1, T1);
    impl_tuple!(ArbitraryTuple2, T1, T2);
    impl_tuple!(ArbitraryTuple3, T1, T2, T3);
    impl_tuple!(ArbitraryTuple4, T1, T2, T3, T4);
    impl_tuple!(ArbitraryTuple5, T1, T2, T3, T4, T5);
    impl_tuple!(ArbitraryTuple6, T1, T2, T3, T4, T5, T6);
    impl_tuple!(ArbitraryTuple7, T1, T2, T3, T4, T5, T6, T7);
    impl_tuple!(ArbitraryTuple8, T1, T2, T3, T4, T5, T6, T7, T8);
    impl_tuple!(ArbitraryTuple9, T1, T2, T3, T4, T5, T6, T7, T8, T9);
    impl_tuple!(ArbitraryTuple10, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10);
    impl_tuple!(
        ArbitraryTuple11,
        T1,
        T2,
        T3,
        T4,
        T5,
        T6,
        T7,
        T8,
        T9,
        T10,
        T11
    );
    impl_tuple!(
        ArbitraryTuple12,
        T1,
        T2,
        T3,
        T4,
        T5,
        T6,
        T7,
        T8,
        T9,
        T10,
        T11,
        T12
    );
}

/// Implementations of `soroban_sdk::testutils::arbitrary::api` for `Val`.
mod composite {
    use arbitrary::Arbitrary;

    use super::api::*;
    use crate::ConversionError;
    use crate::{Env, IntoVal, TryFromVal};

    use super::objects::*;
    use super::simple::*;
    use crate::{
        Address, Bytes, BytesN, Duration, Map, String, Symbol, Timepoint, Val, Vec, I256, U256,
    };

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryVal {
        Void,
        Bool(bool),
        Error(Error),
        U32(u32),
        I32(i32),
        U64(u64),
        I64(i64),
        U128(u128),
        I128(i128),
        U256(ArbitraryU256),
        I256(ArbitraryI256),
        Bytes(ArbitraryBytes),
        String(ArbitraryString),
        Symbol(ArbitrarySymbol),
        Vec(ArbitraryValVec),
        Map(ArbitraryValMap),
        Address(ArbitraryAddress),
        Timepoint(ArbitraryTimepoint),
        Duration(ArbitraryDuration),
        Option(ArbitraryValOption),
    }

    impl SorobanArbitrary for Val {
        type Prototype = ArbitraryVal;
    }

    impl TryFromVal<Env, ArbitraryVal> for Val {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryVal) -> Result<Self, Self::Error> {
            Ok(match v {
                ArbitraryVal::Void => Val::VOID.into(),
                ArbitraryVal::Bool(v) => v.into_val(env),
                ArbitraryVal::Error(v) => v.into_val(env),
                ArbitraryVal::U32(v) => v.into_val(env),
                ArbitraryVal::I32(v) => v.into_val(env),
                ArbitraryVal::U64(v) => v.into_val(env),
                ArbitraryVal::I64(v) => v.into_val(env),
                ArbitraryVal::U256(v) => {
                    let v: U256 = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::I256(v) => {
                    let v: I256 = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::U128(v) => v.into_val(env),
                ArbitraryVal::I128(v) => v.into_val(env),
                ArbitraryVal::Bytes(v) => {
                    let v: Bytes = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::String(v) => {
                    let v: String = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::Symbol(v) => {
                    let v: Symbol = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::Vec(v) => v.into_val(env),
                ArbitraryVal::Map(v) => v.into_val(env),
                ArbitraryVal::Address(v) => {
                    let v: Address = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::Timepoint(v) => {
                    let v: Timepoint = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::Duration(v) => {
                    let v: Duration = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryVal::Option(v) => v.into_val(env),
            })
        }
    }

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryValVec {
        Void(<Vec<()> as SorobanArbitrary>::Prototype),
        Bool(<Vec<bool> as SorobanArbitrary>::Prototype),
        Error(<Vec<Error> as SorobanArbitrary>::Prototype),
        U32(<Vec<u32> as SorobanArbitrary>::Prototype),
        I32(<Vec<i32> as SorobanArbitrary>::Prototype),
        U64(<Vec<u64> as SorobanArbitrary>::Prototype),
        I64(<Vec<i64> as SorobanArbitrary>::Prototype),
        U128(<Vec<u128> as SorobanArbitrary>::Prototype),
        I128(<Vec<i128> as SorobanArbitrary>::Prototype),
        U256(<Vec<U256> as SorobanArbitrary>::Prototype),
        I256(<Vec<I256> as SorobanArbitrary>::Prototype),
        Bytes(<Vec<Bytes> as SorobanArbitrary>::Prototype),
        BytesN(<Vec<BytesN<32>> as SorobanArbitrary>::Prototype),
        String(<Vec<String> as SorobanArbitrary>::Prototype),
        Symbol(<Vec<Symbol> as SorobanArbitrary>::Prototype),
        Vec(<Vec<Vec<u32>> as SorobanArbitrary>::Prototype),
        Map(<Vec<Map<u32, u32>> as SorobanArbitrary>::Prototype),
        Address(<Vec<Address> as SorobanArbitrary>::Prototype),
        Timepoint(<Vec<Timepoint> as SorobanArbitrary>::Prototype),
        Duration(<Vec<Duration> as SorobanArbitrary>::Prototype),
        Val(<Vec<Val> as SorobanArbitrary>::Prototype),
    }

    impl TryFromVal<Env, ArbitraryValVec> for Val {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryValVec) -> Result<Self, Self::Error> {
            Ok(match v {
                ArbitraryValVec::Void(v) => {
                    let v: Vec<()> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Bool(v) => {
                    let v: Vec<bool> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Error(v) => {
                    let v: Vec<Error> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::U32(v) => {
                    let v: Vec<u32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::I32(v) => {
                    let v: Vec<i32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::U64(v) => {
                    let v: Vec<u64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::I64(v) => {
                    let v: Vec<i64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::U128(v) => {
                    let v: Vec<u128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::I128(v) => {
                    let v: Vec<i128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::U256(v) => {
                    let v: Vec<U256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::I256(v) => {
                    let v: Vec<I256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Bytes(v) => {
                    let v: Vec<Bytes> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::BytesN(v) => {
                    let v: Vec<BytesN<32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::String(v) => {
                    let v: Vec<String> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Symbol(v) => {
                    let v: Vec<Symbol> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Vec(v) => {
                    let v: Vec<Vec<u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Map(v) => {
                    let v: Vec<Map<u32, u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Address(v) => {
                    let v: Vec<Address> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Timepoint(v) => {
                    let v: Vec<Timepoint> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Duration(v) => {
                    let v: Vec<Duration> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValVec::Val(v) => {
                    let v: Vec<Val> = v.into_val(env);
                    v.into_val(env)
                }
            })
        }
    }

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryValMap {
        VoidToVoid(<Map<(), ()> as SorobanArbitrary>::Prototype),
        BoolToBool(<Map<bool, bool> as SorobanArbitrary>::Prototype),
        ErrorToError(<Map<Error, Error> as SorobanArbitrary>::Prototype),
        U32ToU32(<Map<u32, u32> as SorobanArbitrary>::Prototype),
        I32ToI32(<Map<i32, i32> as SorobanArbitrary>::Prototype),
        U64ToU64(<Map<u64, u64> as SorobanArbitrary>::Prototype),
        I64ToI64(<Map<i64, i64> as SorobanArbitrary>::Prototype),
        U128ToU128(<Map<u128, u128> as SorobanArbitrary>::Prototype),
        I128ToI128(<Map<i128, i128> as SorobanArbitrary>::Prototype),
        U256ToU256(<Map<U256, U256> as SorobanArbitrary>::Prototype),
        I256ToI256(<Map<I256, I256> as SorobanArbitrary>::Prototype),
        BytesToBytes(<Map<Bytes, Bytes> as SorobanArbitrary>::Prototype),
        BytesNToBytesN(<Map<BytesN<32>, BytesN<32>> as SorobanArbitrary>::Prototype),
        StringToString(<Map<String, String> as SorobanArbitrary>::Prototype),
        SymbolToSymbol(<Map<Symbol, Symbol> as SorobanArbitrary>::Prototype),
        VecToVec(<Map<Vec<u32>, Vec<u32>> as SorobanArbitrary>::Prototype),
        MapToMap(<Map<Map<u32, u32>, Map<u32, u32>> as SorobanArbitrary>::Prototype),
        AddressToAddress(<Map<Address, Address> as SorobanArbitrary>::Prototype),
        TimepointToTimepoint(<Map<Timepoint, Timepoint> as SorobanArbitrary>::Prototype),
        DurationToDuration(<Map<Duration, Duration> as SorobanArbitrary>::Prototype),
        ValToVal(<Map<Val, Val> as SorobanArbitrary>::Prototype),
        OptionToOption(<Map<Option<u32>, Option<u32>> as SorobanArbitrary>::Prototype),
    }

    impl TryFromVal<Env, ArbitraryValMap> for Val {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryValMap) -> Result<Self, Self::Error> {
            Ok(match v {
                ArbitraryValMap::VoidToVoid(v) => {
                    let v: Map<(), ()> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::BoolToBool(v) => {
                    let v: Map<bool, bool> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::ErrorToError(v) => {
                    let v: Map<Error, Error> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::U32ToU32(v) => {
                    let v: Map<u32, u32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::I32ToI32(v) => {
                    let v: Map<i32, i32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::U64ToU64(v) => {
                    let v: Map<u64, u64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::I64ToI64(v) => {
                    let v: Map<i64, i64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::U128ToU128(v) => {
                    let v: Map<u128, u128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::I128ToI128(v) => {
                    let v: Map<i128, i128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::U256ToU256(v) => {
                    let v: Map<U256, U256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::I256ToI256(v) => {
                    let v: Map<I256, I256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::BytesToBytes(v) => {
                    let v: Map<Bytes, Bytes> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::BytesNToBytesN(v) => {
                    let v: Map<BytesN<32>, BytesN<32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::StringToString(v) => {
                    let v: Map<String, String> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::SymbolToSymbol(v) => {
                    let v: Map<Symbol, Symbol> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::VecToVec(v) => {
                    let v: Map<Vec<u32>, Vec<u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::MapToMap(v) => {
                    let v: Map<Map<u32, u32>, Map<u32, u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::AddressToAddress(v) => {
                    let v: Map<Address, Address> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::TimepointToTimepoint(v) => {
                    let v: Map<Timepoint, Timepoint> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::DurationToDuration(v) => {
                    let v: Map<Duration, Duration> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::ValToVal(v) => {
                    let v: Map<Val, Val> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValMap::OptionToOption(v) => {
                    let v: Map<Option<u32>, Option<u32>> = v.into_val(env);
                    v.into_val(env)
                }
            })
        }
    }

    #[derive(Arbitrary, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
    pub enum ArbitraryValOption {
        Void(<Option<()> as SorobanArbitrary>::Prototype),
        Bool(<Option<bool> as SorobanArbitrary>::Prototype),
        Error(<Option<Error> as SorobanArbitrary>::Prototype),
        U32(<Option<u32> as SorobanArbitrary>::Prototype),
        I32(<Option<i32> as SorobanArbitrary>::Prototype),
        U64(<Option<u64> as SorobanArbitrary>::Prototype),
        I64(<Option<i64> as SorobanArbitrary>::Prototype),
        U128(<Option<u128> as SorobanArbitrary>::Prototype),
        I128(<Option<i128> as SorobanArbitrary>::Prototype),
        U256(<Option<U256> as SorobanArbitrary>::Prototype),
        I256(<Option<I256> as SorobanArbitrary>::Prototype),
        Bytes(<Option<Bytes> as SorobanArbitrary>::Prototype),
        BytesN(<Option<BytesN<32>> as SorobanArbitrary>::Prototype),
        String(<Option<String> as SorobanArbitrary>::Prototype),
        Symbol(<Option<Symbol> as SorobanArbitrary>::Prototype),
        Vec(<Option<Vec<u32>> as SorobanArbitrary>::Prototype),
        Map(<Option<Map<u32, u32>> as SorobanArbitrary>::Prototype),
        Address(<Option<Address> as SorobanArbitrary>::Prototype),
        Timepoint(<Option<Timepoint> as SorobanArbitrary>::Prototype),
        Duration(<Option<Duration> as SorobanArbitrary>::Prototype),
        Val(Box<<Option<Val> as SorobanArbitrary>::Prototype>),
    }

    impl TryFromVal<Env, ArbitraryValOption> for Val {
        type Error = ConversionError;
        fn try_from_val(env: &Env, v: &ArbitraryValOption) -> Result<Self, Self::Error> {
            Ok(match v {
                ArbitraryValOption::Void(v) => {
                    let v: Option<()> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Bool(v) => {
                    let v: Option<bool> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Error(v) => {
                    let v: Option<Error> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::U32(v) => {
                    let v: Option<u32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::I32(v) => {
                    let v: Option<i32> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::U64(v) => {
                    let v: Option<u64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::I64(v) => {
                    let v: Option<i64> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::U128(v) => {
                    let v: Option<u128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::I128(v) => {
                    let v: Option<i128> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::U256(v) => {
                    let v: Option<U256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::I256(v) => {
                    let v: Option<I256> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Bytes(v) => {
                    let v: Option<Bytes> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::BytesN(v) => {
                    let v: Option<BytesN<32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::String(v) => {
                    let v: Option<String> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Symbol(v) => {
                    let v: Option<Symbol> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Vec(v) => {
                    let v: Option<Vec<u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Map(v) => {
                    let v: Option<Map<u32, u32>> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Address(v) => {
                    let v: Option<Address> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Timepoint(v) => {
                    let v: Option<Timepoint> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Duration(v) => {
                    let v: Option<Duration> = v.into_val(env);
                    v.into_val(env)
                }
                ArbitraryValOption::Val(v) => {
                    let v: Option<Val> = (**v).into_val(env);
                    v.into_val(env)
                }
            })
        }
    }
}

/// Additional tools for writing fuzz tests.
mod fuzz_test_helpers {
    use soroban_env_host::testutils::call_with_suppressed_panic_hook;

    /// Catch panics within a fuzz test.
    ///
    /// The `cargo-fuzz` test harness turns panics into test failures,
    /// immediately aborting the process.
    ///
    /// This function catches panics while temporarily disabling the
    /// `cargo-fuzz` panic handler.
    ///
    /// # Example
    ///
    /// ```
    /// # macro_rules! fuzz_target {
    /// #     (|$data:ident: $dty: ty| $body:block) => { };
    /// # }
    /// # struct ExampleContract;
    /// # impl ExampleContract {
    /// #   fn new(e: &soroban_sdk::Env, b: &soroban_sdk::BytesN<32>) { }
    /// #   fn deposit(&self, a: soroban_sdk::Address, n: i128) { }
    /// # }
    /// use soroban_sdk::{Address, Env};
    /// use soroban_sdk::testutils::arbitrary::{Arbitrary, SorobanArbitrary};
    ///
    /// #[derive(Arbitrary, Debug)]
    /// struct FuzzDeposit {
    ///     deposit_amount: i128,
    ///     deposit_address: <Address as SorobanArbitrary>::Prototype,
    /// }
    ///
    /// fuzz_target!(|input: FuzzDeposit| {
    ///     let env = Env::default();
    ///
    ///     let contract = ExampleContract::new(env, &env.register_contract(None, ExampleContract {}));
    ///
    ///     let addresses: Address = input.deposit_address.into_val(&env);
    ///     let r = contract.try_deposit(deposit_address, input.deposit_amount);
    /// });
    /// ```
    #[deprecated(note = "use [Env::try_invoke] or the try_ functions on a contract client")]
    pub fn fuzz_catch_panic<F, R>(f: F) -> std::thread::Result<R>
    where
        F: FnOnce() -> R,
    {
        call_with_suppressed_panic_hook(std::panic::AssertUnwindSafe(f))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{
        Address, Bytes, BytesN, Duration, Error, Map, String, Symbol, Timepoint, Val, Vec, I256,
        U256,
    };
    use crate::{Env, IntoVal};
    use arbitrary::{Arbitrary, Unstructured};
    use rand::{RngCore, SeedableRng};

    fn run_test<T>()
    where
        T: SorobanArbitrary,
        T::Prototype: for<'a> Arbitrary<'a>,
    {
        let env = Env::default();
        let mut rng = rand::rngs::StdRng::seed_from_u64(0);
        let mut rng_data = [0u8; 64];

        for _ in 0..100 {
            rng.fill_bytes(&mut rng_data);
            let mut unstructured = Unstructured::new(&rng_data);
            loop {
                match T::Prototype::arbitrary(&mut unstructured) {
                    Ok(input) => {
                        let _val: T = input.into_val(&env);
                        break;
                    }
                    Err(_) => {}
                }
            }
        }
    }

    #[test]
    fn test_unit() {
        run_test::<()>()
    }

    #[test]
    fn test_bool() {
        run_test::<bool>()
    }

    #[test]
    fn test_u32() {
        run_test::<u32>()
    }

    #[test]
    fn test_i32() {
        run_test::<i32>()
    }

    #[test]
    fn test_u64() {
        run_test::<u64>()
    }

    #[test]
    fn test_i64() {
        run_test::<i64>()
    }

    #[test]
    fn test_u128() {
        run_test::<u128>()
    }

    #[test]
    fn test_i128() {
        run_test::<i128>()
    }

    #[test]
    fn test_u256() {
        run_test::<U256>()
    }

    #[test]
    fn test_i256() {
        run_test::<I256>()
    }

    #[test]
    fn test_bytes() {
        run_test::<Bytes>()
    }

    #[test]
    fn test_string() {
        run_test::<String>()
    }

    #[test]
    fn test_bytes_n() {
        run_test::<BytesN<32>>()
    }

    #[test]
    fn test_symbol() {
        run_test::<Symbol>()
    }

    #[test]
    fn test_address() {
        run_test::<Address>()
    }

    #[test]
    fn test_val() {
        run_test::<Val>()
    }

    #[test]
    fn test_vec_void() {
        run_test::<Vec<()>>()
    }

    #[test]
    fn test_vec_bool() {
        run_test::<Vec<bool>>()
    }

    #[test]
    fn test_vec_error() {
        run_test::<Vec<Error>>()
    }

    #[test]
    fn test_vec_u32() {
        run_test::<Vec<u32>>()
    }

    #[test]
    fn test_vec_i32() {
        run_test::<Vec<i32>>()
    }

    #[test]
    fn test_vec_u64() {
        run_test::<Vec<u64>>()
    }

    #[test]
    fn test_vec_i64() {
        run_test::<Vec<i64>>()
    }

    #[test]
    fn test_vec_u128() {
        run_test::<Vec<u128>>()
    }

    #[test]
    fn test_vec_i128() {
        run_test::<Vec<i128>>()
    }

    #[test]
    fn test_vec_u256() {
        run_test::<Vec<U256>>()
    }

    #[test]
    fn test_vec_i256() {
        run_test::<Vec<I256>>()
    }

    #[test]
    fn test_vec_bytes() {
        run_test::<Vec<Bytes>>()
    }

    #[test]
    fn test_vec_bytes_n() {
        run_test::<Vec<BytesN<32>>>()
    }

    #[test]
    fn test_vec_string() {
        run_test::<Vec<String>>()
    }

    #[test]
    fn test_vec_symbol() {
        run_test::<Vec<Symbol>>()
    }

    #[test]
    fn test_vec_vec_u32() {
        run_test::<Vec<Vec<u32>>>()
    }

    #[test]
    fn test_vec_vec_bytes() {
        run_test::<Vec<Vec<Bytes>>>()
    }

    #[test]
    fn test_vec_timepoint() {
        run_test::<Vec<Timepoint>>()
    }

    #[test]
    fn test_vec_duration() {
        run_test::<Vec<Duration>>()
    }

    #[test]
    fn test_vec_map_u32() {
        run_test::<Vec<Map<u32, u32>>>()
    }

    #[test]
    fn test_vec_address() {
        run_test::<Vec<Address>>()
    }

    #[test]
    fn test_vec_val() {
        run_test::<Vec<Val>>()
    }

    #[test]
    fn test_map_void() {
        run_test::<Map<(), ()>>()
    }

    #[test]
    fn test_map_bool() {
        run_test::<Map<bool, bool>>()
    }

    #[test]
    fn test_map_error() {
        run_test::<Map<Error, Error>>()
    }

    #[test]
    fn test_map_u32() {
        run_test::<Map<u32, Vec<u32>>>()
    }

    #[test]
    fn test_map_i32() {
        run_test::<Map<i32, Vec<i32>>>()
    }

    #[test]
    fn test_map_u64() {
        run_test::<Map<u64, Vec<u64>>>()
    }

    #[test]
    fn test_map_i64() {
        run_test::<Map<i64, Vec<i64>>>()
    }

    #[test]
    fn test_map_u128() {
        run_test::<Map<u128, Vec<u128>>>()
    }

    #[test]
    fn test_map_i128() {
        run_test::<Map<i128, Vec<i128>>>()
    }

    #[test]
    fn test_map_u256() {
        run_test::<Map<U256, Vec<U256>>>()
    }

    #[test]
    fn test_map_i256() {
        run_test::<Map<I256, Vec<I256>>>()
    }

    #[test]
    fn test_map_bytes() {
        run_test::<Map<Bytes, Bytes>>()
    }

    #[test]
    fn test_map_bytes_n() {
        run_test::<Map<BytesN<32>, Bytes>>()
    }

    #[test]
    fn test_map_string() {
        run_test::<Map<String, String>>()
    }

    #[test]
    fn test_map_symbol() {
        run_test::<Map<Symbol, Symbol>>()
    }

    #[test]
    fn test_map_vec_u32() {
        run_test::<Map<Vec<u32>, Vec<u32>>>()
    }

    #[test]
    fn test_map_vec_bytes() {
        run_test::<Map<Vec<Bytes>, Vec<Bytes>>>()
    }

    #[test]
    fn test_map_timepoint() {
        run_test::<Map<Timepoint, Timepoint>>()
    }

    #[test]
    fn test_map_duration() {
        run_test::<Map<Duration, Duration>>()
    }

    fn test_map_map_u32() {
        run_test::<Map<Map<u32, u32>, Map<u32, u32>>>()
    }

    #[test]
    fn test_map_address() {
        run_test::<Map<Address, Address>>()
    }

    #[test]
    fn test_map_val() {
        run_test::<Map<Val, Val>>()
    }

    #[test]
    fn test_timepoint() {
        run_test::<Timepoint>()
    }

    #[test]
    fn test_duration() {
        run_test::<Duration>()
    }

    #[test]
    fn test_tuples() {
        run_test::<(u32,)>();
        run_test::<(u32, u32)>();
        run_test::<(u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32)>();
        run_test::<(u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32)>();

        run_test::<(u32, Address, Vec<Timepoint>, Map<Duration, u64>)>();
    }

    #[test]
    fn test_option() {
        run_test::<Option<u32>>();
        run_test::<Option<Vec<u32>>>();
    }

    // Test that sometimes generated vecs have the wrong element types.
    #[test]
    fn test_vec_wrong_types() {
        // These number are tuned for StdRng.
        // If StdRng ever changes the test could break.
        let iterations = 1000;
        let seed = 3;
        let acceptable_ratio = 900;

        let (mut seen_good, mut seen_bad, mut seen_empty) = (0, 0, 0);

        let env = Env::default();
        let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
        let mut rng_data = [0u8; 64];

        for _ in 0..iterations {
            rng.fill_bytes(&mut rng_data);
            let mut unstructured = Unstructured::new(&rng_data);
            let input = <Vec<u32> as SorobanArbitrary>::Prototype::arbitrary(&mut unstructured)
                .expect("SorobanArbitrary");
            let vec: Vec<u32> = input.into_val(&env);

            let has_good_elts = (0..vec.len()).all(|i| vec.try_get(i).is_ok()) && !vec.is_empty();
            // Look for elements that cause an error.
            let has_bad_elt = (0..vec.len()).any(|i| vec.try_get(i).is_err());

            if has_bad_elt {
                seen_bad += 1;
            } else if has_good_elts {
                seen_good += 1;
            } else {
                seen_empty += 1;
            }
        }

        assert!(seen_good > 0);
        assert!(seen_bad > 0);

        // sanity check the ratio of good to bad
        assert!(seen_good * seen_empty > seen_bad * acceptable_ratio);
    }

    // Test that sometimes generated maps have the wrong element types.
    #[test]
    fn test_map_wrong_types() {
        // These number are tuned for StdRng.
        // If StdRng ever changes the test could break.
        let iterations = 4000;
        let seed = 13;
        let acceptable_ratio = 900;

        let (mut seen_good, mut seen_bad_key, mut seen_bad_value, mut seen_empty) = (0, 0, 0, 0);

        let env = Env::default();
        let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
        let mut rng_data = [0u8; 128];

        for _ in 0..iterations {
            rng.fill_bytes(&mut rng_data);
            let mut unstructured = Unstructured::new(&rng_data);
            let input =
                <Map<u32, u32> as SorobanArbitrary>::Prototype::arbitrary(&mut unstructured)
                    .expect("SorobanArbitrary");
            let map: Map<u32, u32> = input.into_val(&env);

            // Look for elements that cause an error.
            let keys = map.keys();
            let values = map.values();

            let has_good_keys =
                (0..keys.len()).all(|i| keys.try_get(i).is_ok()) && !keys.is_empty();
            let has_good_values =
                (0..values.len()).all(|i| values.try_get(i).is_ok()) && !keys.is_empty();
            let has_bad_key = (0..keys.len()).any(|i| keys.try_get(i).is_err());
            let has_bad_value = (0..values.len()).any(|i| values.try_get(i).is_err());

            if has_bad_key {
                seen_bad_key += 1;
            } else if has_bad_value {
                seen_bad_value += 1;
            } else if has_good_keys && has_good_values {
                seen_good += 1;
            } else {
                seen_empty += 1;
            }
        }

        assert!(seen_good > 0);
        assert!(seen_bad_key > 0);
        assert!(seen_bad_value > 0);

        // sanity check the ratio of good to bad
        assert!(seen_good * seen_empty > (seen_bad_key + seen_bad_value) * acceptable_ratio);
    }

    mod user_defined_types {
        use super::run_test;
        use crate as soroban_sdk;
        use crate::{
            Address, Bytes, BytesN, Duration, Error, Map, Symbol, Timepoint, Vec, I256, U256,
        };
        use soroban_sdk::contracttype;

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        struct PrivStruct {
            count_u: u32,
            count_i: i32,
            bytes_n: BytesN<32>,
            vec: Vec<Bytes>,
            map: Map<Bytes, Vec<i32>>,
            u256: U256,
            i156: I256,
            error: Error,
            address: Address,
            symbol: Symbol,
            duration: Duration,
            timepoint: Timepoint,
            nil: (),
            vec_tuple: Vec<(u32, Address)>,
            option: Option<u32>,
        }

        #[test]
        fn test_user_defined_priv_struct() {
            run_test::<PrivStruct>();
        }

        #[test]
        fn test_option_user_defined_priv_struct() {
            run_test::<Option<PrivStruct>>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        struct PrivStructPubFields {
            pub count_u: u32,
            pub count_i: i32,
            pub bytes_n: BytesN<32>,
            pub vec: Vec<Bytes>,
            pub map: Map<Bytes, Vec<i32>>,
        }

        #[test]
        fn test_user_defined_priv_struct_pub_fields() {
            run_test::<PrivStructPubFields>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub struct PubStruct {
            count_u: u32,
            count_i: i32,
            bytes_n: BytesN<32>,
            vec: Vec<Bytes>,
            map: Map<Bytes, Vec<i32>>,
        }

        #[test]
        fn test_user_defined_pub_struct() {
            run_test::<PubStruct>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub struct PubStructPubFields {
            pub count_u: u32,
            pub count_i: i32,
            pub bytes_n: BytesN<32>,
            pub vec: Vec<Bytes>,
            pub map: Map<Bytes, Vec<i32>>,
        }

        #[test]
        fn test_user_defined_pubstruct_pub_fields() {
            run_test::<PubStructPubFields>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        struct PrivTupleStruct(
            u32,
            i32,
            BytesN<32>,
            Vec<Bytes>,
            Map<Bytes, Vec<i32>>,
            Vec<(u32, Address)>,
            Option<u32>,
        );

        #[test]
        fn test_user_defined_priv_tuple_struct() {
            run_test::<PrivTupleStruct>();
        }

        #[test]
        fn test_option_user_defined_priv_tuple_struct() {
            run_test::<Option<PrivTupleStruct>>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        struct PrivTupleStructPubFields(
            pub u32,
            pub i32,
            pub BytesN<32>,
            pub Vec<Bytes>,
            pub Map<Bytes, Vec<i32>>,
            pub Vec<(u32, Address)>,
        );

        #[test]
        fn test_user_defined_priv_tuple_struct_pub_fields() {
            run_test::<PrivTupleStructPubFields>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub struct PubTupleStruct(u32, i32, BytesN<32>, Vec<Bytes>, Map<Bytes, Vec<i32>>);

        #[test]
        fn test_user_defined_pub_tuple_struct() {
            run_test::<PubTupleStruct>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub struct PubTupleStructPubFields(
            pub u32,
            pub i32,
            pub BytesN<32>,
            pub Vec<Bytes>,
            pub Map<Bytes, Vec<i32>>,
            pub Vec<(u32, Address)>,
        );

        #[test]
        fn test_user_defined_pub_tuple_struct_pub_fields() {
            run_test::<PubTupleStructPubFields>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub(crate) struct PubCrateStruct(u32);

        #[test]
        fn test_user_defined_pub_crate_struct() {
            run_test::<PubCrateStruct>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        enum PrivEnum {
            A(u32),
            Aa(u32, u32),
            C,
            D,
            E(Vec<(u32, Address)>),
            F(Option<u32>),
        }

        #[test]
        fn test_user_defined_priv_enum() {
            run_test::<PrivEnum>();
        }

        #[test]
        fn test_option_user_defined_priv_enum() {
            run_test::<Option<PrivEnum>>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub enum PubEnum {
            A(u32),
            C,
            D,
        }

        #[test]
        fn test_user_defined_pub_enum() {
            run_test::<PubEnum>();
        }

        #[contracttype]
        #[derive(Clone, Debug, Eq, PartialEq)]
        pub(crate) enum PubCrateEnum {
            A(u32),
            C,
            D,
        }

        #[test]
        fn test_user_defined_pub_crate_enum() {
            run_test::<PubCrateEnum>();
        }

        #[contracttype]
        #[derive(Copy, Clone, Debug, Eq, PartialEq)]
        enum PrivEnumInt {
            A = 1,
            C = 2,
            D = 3,
        }

        #[test]
        fn test_user_defined_priv_enum_int() {
            run_test::<PrivEnumInt>();
        }

        #[contracttype]
        #[derive(Copy, Clone, Debug, Eq, PartialEq)]
        pub enum PubEnumInt {
            A = 1,
            C = 2,
            D = 3,
        }

        #[test]
        fn test_user_defined_pub_enum_int() {
            run_test::<PubEnumInt>();
        }

        #[test]
        fn test_declared_inside_a_fn() {
            #[contracttype]
            struct Foo {
                a: u32,
            }

            #[contracttype]
            enum Bar {
                Baz,
                Qux,
            }

            run_test::<Foo>();
            run_test::<Bar>();
        }

        fn test_structs_and_enums_inside_tuples() {
            #[contracttype]
            struct Foo(u32);

            #[contracttype]
            enum Bar {
                Baz,
            }

            run_test::<(Foo, Bar)>();
        }
    }
}