Struct DevRng 

pub struct DevRng(/* private fields */);

Reproducible random generator for tests

Implementations

impl DevRng

pub fn new() -> Self

Constructs randomness generator

Reads a seed from env variable RUST_TESTS_SEED or generates a random seed if env variable is not set. Prints seed to stderr.

Panics if RUST_TESTS_SEED contains invalid value.

pub fn fork(&mut self) -> Self

Derives another randomness generator from this instance

Uses self to generate a seed and constructs a new instance of DevRng from the seed.

May be useful when you have several threads/futures/places where you need access the randomness generation, but you don’t want to mess with ownership system.

pub fn get_seed(&self) -> [u8; 32]

Retrieves generator seed

Trait Implementations

impl Clone for DevRng

fn clone(&self) -> DevRng

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DevRng

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

Formats the value using the given formatter.

impl Default for DevRng

fn default() -> Self

Returns the “default value” for a type.

impl RngCore for DevRng

fn next_u32(&mut self) -> u32

Return the next random u32.

fn next_u64(&mut self) -> u64

Return the next random u64.

fn fill_bytes(&mut self, dest: &mut [u8])

Fill dest with random data.

impl SeedableRng for DevRng

type Seed = <ChaCha8Rng as SeedableRng>::Seed

Seed type, which is restricted to types mutably-dereferenceable as u8 arrays (we recommend [u8; N] for some N).

fn from_seed(seed: Self::Seed) -> Self

Create a new PRNG using the given seed.

fn seed_from_u64(state: u64) -> Self

Create a new PRNG using a u64 seed.

fn from_rng(rng: &mut impl RngCore) -> Self

Create a new PRNG seeded from an infallible Rng.

fn try_from_rng<R: TryRngCore>(rng: &mut R) -> Result<Self, R::Error>

Create a new PRNG seeded from a potentially fallible Rng.

fn from_os_rng() -> Self

Creates a new instance of the RNG seeded via getrandom.

fn try_from_os_rng() -> Result<Self, Error>

Creates a new instance of the RNG seeded via getrandom without unwrapping potential getrandom errors.

impl CryptoRng for DevRng