[−][src]Struct proptest::test_runner::TestRng
Proptest's random number generator.
Implementations
impl TestRng
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pub fn from_seed(algorithm: RngAlgorithm, seed: &[u8]) -> Self
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Create a new RNG with the given algorithm and seed.
Any RNG created with the same algorithm-seed pair will produce the same sequence of values on all systems and all supporting versions of proptest.
Panics
Panics if seed
is not an appropriate length for algorithm
.
pub fn bytes_used(&self) -> Vec<u8>ⓘ
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Dumps the bytes obtained from the RNG so far (only works if the RNG is
set to Recorder
).
Panics
Panics if this RNG does not capture generated data.
pub fn deterministic_rng(algorithm: RngAlgorithm) -> Self
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Returns a TestRng
with a particular hard-coded seed.
The seed value will always be the same for a particular version of Proptest and algorithm, but may change across releases.
This is useful for testing things like strategy implementations without
risking getting "unlucky" RNGs which deviate from average behaviour
enough to cause spurious failures. For example, a strategy for bool
which is supposed to produce true
50% of the time might have a test
which checks that the distribution is "close enough" to 50%. If every
test run starts with a different RNG, occasionally there will be
spurious test failures when the RNG happens to produce a very skewed
distribution. Using this or TestRunner::deterministic()
avoids such
issues.
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for TestRng
impl Send for TestRng
impl Sync for TestRng
impl Unpin for TestRng
impl UnwindSafe for TestRng
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<R> Rng for R where
R: RngCore + ?Sized,
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R: RngCore + ?Sized,
fn gen<T>(&mut self) -> T where
Standard: Distribution<T>,
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Standard: Distribution<T>,
fn gen_range<T, B1, B2>(&mut self, low: B1, high: B2) -> T where
B1: SampleBorrow<T>,
B2: SampleBorrow<T>,
T: SampleUniform,
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B1: SampleBorrow<T>,
B2: SampleBorrow<T>,
T: SampleUniform,
fn sample<T, D>(&mut self, distr: D) -> T where
D: Distribution<T>,
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D: Distribution<T>,
fn sample_iter<T, D>(self, distr: D) -> DistIter<D, Self, T> where
D: Distribution<T>,
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D: Distribution<T>,
fn fill<T>(&mut self, dest: &mut T) where
T: AsByteSliceMut + ?Sized,
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T: AsByteSliceMut + ?Sized,
fn try_fill<T>(&mut self, dest: &mut T) -> Result<(), Error> where
T: AsByteSliceMut + ?Sized,
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T: AsByteSliceMut + ?Sized,
fn gen_bool(&mut self, p: f64) -> bool
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fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
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impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,