Sampling & exporting

Sampling a generator

Gen::sample() eagerly generates values from any arbitrary for a fixed seed — a quick way to eyeball what a generator produces (it returns values, not an arbitrary).

Gen::sample(Gen::intBetween(1, 6), count: 5, seed: 42); // [3, 1, 6, 6, 2]

Gen::sampleShrinks() does the same for the shrink tree: it generates one value and lists its first direct shrink candidates — the fastest way to check that a custom arbitrary shrinks the way you intended.

Gen::sampleShrinks(Gen::intBetween(0, 100), seed: 1);
// ['value' => 87, 'shrinks' => [0, 44, 66, 77, 82, 85, 86]]

Exporting a counterexample

CounterExample::toArray() and toJson() expose a normalized representation for reporters and CI artifacts, including nested DTO state and recursion markers. To pin a shrunk scalar/array/enum case as a regression example:

$code = $violation->getCounterExample()->toExamplesCode('holdsExamples');

The generated method yields arguments in parameter order. Unsupported runtime objects throw LogicException instead of producing code that cannot run.