Struct QuickcheckTree 

pub struct QuickcheckTree<T> { /* private fields */ }

Adapts quickcheck’s linear shrink iterator to the seam’s ValueTree.

quickcheck has no complicate step: Arbitrary::shrink is a flat iterator of smaller candidates. This tree maps that onto the simplify/complicate protocol the runner drives. accepted is the simplest value seen to still fail; siblings is its remaining shrink candidates; candidate is the one handed to the runner but not yet judged.

• simplify, called again after the runner adopted a candidate, promotes that candidate to accepted and shrinks it; then it hands out the next sibling. The runner calling simplify again is the signal that the last candidate reproduced the failure.
• complicate, called when a candidate did not reproduce the failure, discards it and tries the next sibling instead. This is how every candidate in quickcheck’s flat iterator gets a turn.

Trait Implementations

impl<T> ValueTree<T> for QuickcheckTree<T>

where T: Arbitrary,

fn current(&self) -> T

The current value.

fn simplify(&mut self) -> bool

Replaces the current value with a simpler one. Returns true if it moved, false if the value is already as simple as the tree can make it.

fn complicate(&mut self) -> bool

Walks back toward the last value that still failed, undoing a simplify that shrank past the failure. Returns true if it moved.