HookOrderTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\Core\Hook;

use Drupal\Core\Hook\HookOrder;

/**
 * @coversDefaultClass \Drupal\Core\Hook\HookOrder
 *
 * @group Hook
 */
class HookOrderTest extends HookOrderTestBase {
    
    /**
     * The original priorities.
     *
     * @var array
     */
    protected array $originalPriorities = [];
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        // "c" first, "b" second, "a" last.
        $this->setUpContainer(TRUE);
        foreach ([
            'a',
            'b',
            'c',
        ] as $key) {
            $this->originalPriorities[$key] = $this->getPriority($key);
        }
        // The documentation does not clarify the order of arguments, let's do so
        // here to make it easier to develop/debug this test.
        $this->assertGreaterThan(1, 2);
        // According to https://symfony.com/doc/current/event_dispatcher.html
        // the higher the number, the earlier a listener is executed. Accordingly
        // assert that "a" is last, "c" is first, "b" is in the middle. The
        // asserts in methods can be compared to these establishing asserts.
        $this->assertGreaterThan($this->getPriority('a'), $this->getPriority('b'));
        $this->assertGreaterThan($this->getPriority('b'), $this->getPriority('c'));
        // This is unnecessary but asserts are free, and it's easier to compare if
        // this is explicit.
        $this->assertGreaterThan($this->getPriority('a'), $this->getPriority('c'));
    }
    
    /**
     * @covers ::first
     */
    public function testFirst() : void {
        // "c" was first, make "a" the first.
        HookOrder::first($this->container, 'test', 'a::a');
        $this->assertGreaterThan($this->getPriority('c'), $this->getPriority('a'));
        $this->assertGreaterThan($this->getPriority('b'), $this->getPriority('a'));
        // The other two shouldn't change.
        $this->assertNoChange('a');
    }
    
    /**
     * @covers ::last
     */
    public function testLast() : void {
        // "c" was first, make it the last.
        HookOrder::last($this->container, 'test', 'c::c');
        $this->assertGreaterThan($this->getPriority('c'), $this->getPriority('a'));
        $this->assertGreaterThan($this->getPriority('c'), $this->getPriority('b'));
        // The other two shouldn't change.
        $this->assertNoChange('c');
    }
    
    /**
     * @covers ::before
     */
    public function testBefore() : void {
        // "a" was last, move it before "b".
        HookOrder::before($this->container, 'test', 'a::a', 'b::b');
        $this->assertGreaterThan($this->getPriority('b'), $this->getPriority('a'));
        // The relation between these should not change. The actual priority
        // might.
        $this->assertGreaterThan($this->getPriority('b'), $this->getPriority('c'));
        $this->assertGreaterThan($this->getPriority('a'), $this->getPriority('c'));
    }
    
    /**
     * @covers ::after
     */
    public function testAfter() : void {
        // "c" was first, move it after "b".
        HookOrder::after($this->container, 'test', 'c::c', 'b::b');
        $this->assertGreaterThan($this->getPriority('c'), $this->getPriority('b'));
        // The relation between these should not change. The actual priority
        // might.
        $this->assertGreaterThan($this->getPriority('a'), $this->getPriority('b'));
        $this->assertGreaterThan($this->getPriority('a'), $this->getPriority('c'));
    }
    
    /**
     * @covers ::first
     */
    public function testFirstNoChange() : void {
        // "c" was first, making it first should be a no-op.
        HookOrder::first($this->container, 'test', 'c::c');
        $this->assertNoChange();
    }
    
    /**
     * @covers ::last
     */
    public function testLastNoChange() : void {
        // "a" was last, making it last should be a no-op.
        HookOrder::last($this->container, 'test', 'a::a');
        $this->assertNoChange();
    }
    
    /**
     * @covers ::before
     */
    public function testBeforeNoChange() : void {
        // "b" is already firing before "a", this should be a no-op.
        HookOrder::before($this->container, 'test', 'b::b');
        $this->assertNoChange();
    }
    
    /**
     * @covers ::after
     */
    public function testAfterNoChange() : void {
        // "b' is already firing after "c", this should be a no-op.
        HookOrder::after($this->container, 'test', 'b::b');
        $this->assertNoChange();
    }
    
    /**
     * Get the priority for a service.
     */
    protected function getPriority(string $name) : int {
        $definition = $this->container
            ->getDefinition($name);
        return $definition->getTags()['kernel.event_listener'][0]['priority'];
    }
    
    /**
     * Asserts no change has happened.
     *
     * @param string $changed
     *   This one did change. Assert the rest did not change.
     */
    protected function assertNoChange(string $changed = '') : void {
        foreach ($this->originalPriorities as $key => $priority) {
            if ($key !== $changed) {
                $this->assertSame($priority, $this->getPriority($key));
            }
        }
    }

}