README

Rector rules to convert test suites between Pest, PHPUnit and Testo.

Directions & config sets

Each direction ships a Rector set under config/sets/:

Conversions that have no faithful counterpart in the target framework (PHPUnit mocks, constraints, memory-leak / retry / repeat, Pest higher-order & arch() tests, etc.) are not silently dropped: each is a documented stub rule plus an entry in the direction's TODO.md.

Argument order (important)

Testo's comparison assertions are (actual, expected); PHPUnit's are (expected, actual). Both AssertCall* rules swap the first two arguments accordingly — getting this wrong would silently invert every comparison, so it is covered by fixtures.

Why Testo → PHPUnit

Testo is self-hosted: the engine that discovers and runs tests is the same code Infection mutates. A mutation on the run path (e.g. Sorter, PipeOptions) can break discovery itself, producing spurious survivors/kills instead of a real mutation signal. Converting the unit-style self-tests to PHPUnit lets Infection's PHPUnit adapter run them on a runner that shares no code with the mutated engine — a mutation can then only be caught (or missed) by an assertion, never by breaking the harness.

Usage

// rector.php
use Rector\Config\RectorConfig;

return RectorConfig::configure()
    ->withPaths([__DIR__ . '/tests'])
    ->withSets([__DIR__ . '/vendor/testo/bridge-rector/config/sets/testo-to-phpunit.php']);

Testing the rules — "inline tests for rules"

The rules are tested by Testo itself, with no PHPUnit dependency. A rule carries #[\Testo\Bridge\Rector\Testing\TestRectorFixtures('<dir>')] pointing at co-located *.php.inc fixtures (input + expected, separated by a ----- line; no separator = "must stay unchanged"). The reusable harness lives in src/Testing/ — attach RectorTestingPlugin to a suite whose finder scans the rule sources, and each fixture is run through a freshly-booted Rector container and reported as its own data set. Fixtures are export-ignored; the harness ships so downstream rule authors can reuse it (testo/* are require-dev + suggest).