Trait ProptestResultExt

pub trait ProptestResultExt<T, E>: Sealed

Extension trait for Result<T, E> to provide additional functionality specifically for prop test cases.

Required Methods

fn prop_assume_ok(self) -> Result<T, TestCaseError>
where
    E: Debug,

Converts a Result<T, E> into a Result<T, TestCaseError>, where the Err case is transformed into a TestCaseError::Reject.

This is intended to be used like the prop_assume! macro, but for fallible computations. If the result is Err, the test input is rejected and a new input will be generated.

Example

use proptest::prelude::*;

fn test_conversion(a: i32) -> Result<(), TestCaseError> {
    // Reject the case if `a` cannot be converted to u8 (e.g., negative values)
    let _unsigned: u8 = a.try_into().prop_assume_ok()?;
    // ...rest of test...
    Ok(())
}

proptest! {
  #[test]
  fn test_that_only_works_with_positive_integers(a in -10i32..10i32) {
    test_conversion(a)?;
  }
}

Implementors