Shrinkable

Rasuvaeff\PropertyTesting\Shrinkable

Class — Package: property-testing-core — Source — Version: v0.1.0-12-g86ead85

Type parameters:

• TValue of mixed = mixed The type of the carried value

A generated value together with a lazy tree of progressively "smaller" variants of it — the unit of integrated shrinking.

Every ArbitraryInterface::generate() call returns one of these. The property runner reads $value, and when the property fails it walks shrinks(): each child is a smaller candidate that carries its own subtree, so accepting a candidate immediately provides the next round of even smaller candidates. Because the tree is built at generation time, a transformed arbitrary (Gen::map(), Gen::flatMap()) shrinks in the source domain and re-applies the transformation — no inverse function is ever needed.

Children are produced lazily (the closure runs only when the runner asks), so building a node costs nothing until shrinking actually happens.

Constructor

__construct(
    \TValue $value,
    callable $shrinks,
)

Parameter	Type	Default	Description
$value	TValue	required
$shrinks	callable	required

Methods

leaf()

static leaf(\T $value): self

A value with no smaller variants (terminal node).

of()

static of(\T $value, callable $shrinks): self

A value with lazily-computed smaller variants, ordered most aggressive first (typically toward a zero/empty/identity element).

shrinks()

shrinks(): iterable

The smaller variants of this value, each with its own subtree.

map()

map(callable $map): self

Transform the whole tree through a pure function: the value and, lazily, every shrink candidate. This is what makes Gen::map() shrink.