[][src]Enum proptest::test_runner::RngAlgorithm

pub enum RngAlgorithm {
    // some variants omitted

Identifies a particular RNG algorithm supported by proptest.

Proptest supports dynamic configuration of algorithms to allow it to continue operating with persisted regression files and to allow the configuration to be expressed in the Config struct.



The XorShift algorithm. This was the default up through and including Proptest 0.9.0.

It is faster than ChaCha but produces lower quality randomness and has some pathological cases where it may fail to produce outputs that are random even to casual observation.

The seed must be exactly 16 bytes.


The ChaCha algorithm. This became the default with Proptest 0.9.1.

The seed must be exactly 32 bytes.


This is not an actual RNG algorithm, but instead returns data directly from its "seed".

This is useful when Proptest is being driven from some other entropy source, such as a fuzzer.

If the seed is depleted, the RNG will return 0s forever.

Note that in cases where a new RNG is to be derived from an existing one, the data is split evenly between them, regardless of how much entropy is actually needed. This means that combinators like prop_perturb and prop_flat_map can require extremely large inputs.


This is equivalent to the ChaCha RNG, with the addition that it records the bytes used to create a value.

This is useful when Proptest is used for fuzzing, and a corpus of initial inputs need to be created. Note that in these cases, you need to use the TestRunner API directly yourself instead of using the proptest! macro, as otherwise there is no way to obtain the bytes this captures.

Trait Implementations

impl Clone for RngAlgorithm[src]

impl Copy for RngAlgorithm[src]

impl Debug for RngAlgorithm[src]

impl Default for RngAlgorithm[src]

impl Display for RngAlgorithm[src]

impl Eq for RngAlgorithm[src]

impl FromStr for RngAlgorithm[src]

type Err = ()

The associated error which can be returned from parsing.

impl PartialEq<RngAlgorithm> for RngAlgorithm[src]

impl StructuralEq for RngAlgorithm[src]

impl StructuralPartialEq for RngAlgorithm[src]

Auto Trait Implementations

impl RefUnwindSafe for RngAlgorithm[src]

impl Send for RngAlgorithm[src]

impl Sync for RngAlgorithm[src]

impl Unpin for RngAlgorithm[src]

impl UnwindSafe for RngAlgorithm[src]

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized

impl<T> Borrow<T> for T where
    T: ?Sized

impl<T> BorrowMut<T> for T where
    T: ?Sized

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 

impl<T> ToOwned for T where
    T: Clone

type Owned = T

The resulting type after obtaining ownership.

impl<T> ToString for T where
    T: Display + ?Sized

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<V, T> VZip<V> for T where
    V: MultiLane<T>,