Struct qcheck::Gen

pub struct Gen { /* private fields */ }

Gen represents a PRNG.

It is the source of randomness from which QuickCheck will generate values. An instance of Gen is passed to every invocation of Arbitrary::arbitrary, which permits callers to use lower level RNG routines to generate values.

It is unspecified whether this is a secure RNG or not. Therefore, callers should assume it is insecure.

Implementations

impl Gen

pub fn new(size: usize) -> Gen

Returns a Gen with a random seed and the given size configuration.

pub fn from_seed(seed: u64) -> Gen

Returns a Gen with the given seed and a default size configuration.

Two Gens created with the same seed will generate the same values. Though the values may vary between QuickCheck releases.

pub fn set_size(&mut self, size: usize)

Sets the size configuration for this generator.

The size parameter controls the size of random values generated. For example, it specifies the maximum length of a randomly generated vector, but is and should not be used to control the range of a randomly generated number. (Unless that number is used to control the size of a data structure.)

pub fn size(&self) -> usize

Returns the size configured with this generator.

pub fn choose<'a, T>(&mut self, slice: &'a [T]) -> Option<&'a T>

Choose among the possible alternatives in the slice given. If the slice is empty, then None is returned. Otherwise, a non-None value is guaranteed to be returned.

pub fn fill<S, T>(&mut self, slice: S)where
    T: Arbitrary,
    S: AsMut<[T]>,

Fill a mutable slice of any Arbitrary-compatible type with Arbitrary values.

Trait Implementations

impl Default for Gen

fn default() -> Self

Returns the “default value” for a type.