Enum Backend 

pub enum Backend {
    Default,
    Urandom,
}

Selects the source of randomness the engine draws from.

Mirrors Hypothesis’s backend setting (specifically backend="hypothesis" vs backend="hypothesis-urandom").

Variants

Default

The default: generate from a seeded pseudo-random generator. Runs are reproducible from Settings::seed and shrinking/replay work as usual.

Urandom

Read fresh entropy from /dev/urandom on every draw, instead of expanding a single PRNG seed.

This exists for running under Antithesis, whose fuzzer controls the bytes returned by /dev/urandom. Sourcing every choice from the OS random device hands the fuzzer control over the entire test case (rather than just the PRNG seed), so it can steer and reproduce generation directly. When running inside Antithesis this backend is selected automatically unless you set one explicitly.

The generation algorithm is otherwise unchanged — only the random source differs. On platforms without /dev/urandom (Windows) it falls back to an OS-seeded PRNG. You almost certainly don’t want this backend unless you are running under Antithesis.

Trait Implementations

impl Clone for Backend

fn clone(&self) -> Backend

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Backend

impl Debug for Backend

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Backend

impl PartialEq for Backend

fn eq(&self, other: &Backend) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Backend