heyjordanparker/mago-pest

Mago Pest

A Mago analyzer extension that types Pest test files the way Pest runs them.

Without it, Mago reads a Pest test file as plain PHP. It cannot see the test case class that $this refers to inside a test closure, so every call to a test case method or helper trait, and every property a beforeEach hook sets, is reported. Expectation chains are reported too, because Pest dispatches most of them through __call and __get.

With it, Mago analyzes:

• $this in test(), it(), beforeEach(), and afterEach() closures, and in the beforeEach() and afterEach() hooks of pest() and uses(), as the test case Pest builds from pest()->extend(), pest()->use(), uses(), and their in() targets.
• Properties that those closures assign to $this, typed by the assigned values.
• Matcher chains: expect($value)->toBe(1)->not->toBeNull()->each->toBeInt().
• Higher-order expectations: expect($user)->name->toBe('Ada') and expect($user)->domain()->toBe('example.com').
• Custom matchers from expect()->extend('name', closure), with the closure's parameters.
• toThrow() with a closure typed by the exception it expects.

Install

composer require --dev carthage-software/mago heyjordanparker/mago-pest

The project owns its worker entrypoint. Create .mago/extensions.php:

<?php

declare(strict_types=1);

use Mago\Sdk\Worker;
use MagoPest\PestExtension;

require dirname(__DIR__) . '/vendor/autoload.php';

(new Worker(PestExtension::create()))->run();

Register it in mago.toml:

[extension-hosts.pest]
command = ["php", ".mago/extensions.php"]

PestExtension::create() takes one option, testDirectory. It is Pest's test directory relative to the Mago workspace, and it defaults to tests:

(new Worker(PestExtension::create(testDirectory: 'src/Tests')))->run();

A worker can host several extensions:

(new Worker(App\Mago\Extension::create(), PestExtension::create()))->run();

How it works

Before Mago parses the project, the extension reads every PHP file under the test directory. For each test file it declares the class Pest generates, P\<path>, with the same parent class and traits Pest gives it. Each pest() or uses() declaration with hooks gets a class of its own, and test files share the properties those hooks assign.

Pest marks its generated class #[AllowDynamicProperties]. Mago does not model that attribute, so the declared class has __get and __set instead. Mago therefore reports a property that no closure assigns as non-documented-property, not non-existent-property.

A property's type is the union of every value assigned to it. The extension reads each value from its tokens, so it can type only a value whose tokens state the type:

• a literal, a string, an array, or a cast
• new of a named class
• a closure, typed by its own signature
• one call to a function, a static method, or a method on $this, typed by its declared return type

Any other value is mixed. That includes a variable, an array access, a chained call, an arithmetic expression, and a return type that depends on templates. A property assigned any mixed value is mixed.

Limits

• Closures in a describe() body outside a test or hook do not run on a test case, and Pest does not bind $this in them. Mago reports $this there, as it should.
• Closure::bind() and Closure::call() rebind $this at runtime, and the extension does not follow them.
• A pest() or uses() declaration is read only when its classes are given as Name::class or as a string, and its in() targets as strings or __DIR__.

Development

composer install
just check

just check validates composer.json, then checks formatting, lints, analyzes the source, and runs the corpus. The corpus in tests/corpus runs the real worker over Pest test files and checks every inline @mago-expect annotation. A test in it that passes shows a capability, and an annotated line shows a defect the extension still reports.

License

MIT