HookStyleServiceListenerTest - Add test for running `hook_foo(&$alter…

…able)`

tests/phpunit/Civi/Core/Event/HookStyleServiceListenerTest.php

@@ -0,0 +1,81 @@
+<?php
+
+namespace Civi\Core\Event;
+
+use Civi\Core\Container;
+use Civi\Core\HookInterface;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+/**
+ * Register a service (eg 'test.hssvlt') with a hook method (eg `function hook_civicrm_hssvlt()`).
+ * Ensure that the hook method can alter data.
+ */
+class HookStyleServiceListenerTest extends \CiviUnitTestCase {
+
+  public function tearDown(): void {
+    HookStyleServiceListenerTestExample::$notes = [];
+    parent::tearDown();
+  }
+
+  public function testDispatch() {
+    $changeMe = $rand = rand(0, 16384);
+
+    $this->useCustomContainer(function (ContainerBuilder $container) use ($rand) {
+      $container->register('test.hssvlt', HookStyleServiceListenerTestExample::class)
+        ->addArgument($rand)
+        ->addTag('event_subscriber')
+        ->setPublic(TRUE);
+    });
+
+    $d = \Civi::dispatcher();
+
+    // Baseline
+    $this->assertEquals([], HookStyleServiceListenerTestExample::$notes);
+    $this->assertEquals($changeMe, $rand);
+
+    // First call - instantiate and run
+    $d->dispatch('hook_civicrm_hssvlt', GenericHookEvent::create(['foo' => &$changeMe]));
+    $this->assertEquals($changeMe, 1 + $rand);
+    $this->assertEquals(["construct($rand)", "fired($rand)"], HookStyleServiceListenerTestExample::$notes);
+
+    // Second call - reuse and run
+    $d->dispatch('hook_civicrm_hssvlt', GenericHookEvent::create(['foo' => &$changeMe]));
+    $this->assertEquals($changeMe, 2 + $rand);
+    $this->assertEquals(["construct($rand)", "fired($rand)", "fired(" . ($rand + 1) . ")"], HookStyleServiceListenerTestExample::$notes);
+  }
+
+  /**
+   * Create and activate a custom service-container.
+   *
+   * @param callable $callback
+   *   Callback function which will modify the container.
+   *   function(ContainerBuilder $container)
+   */
+  protected function useCustomContainer(callable $callback) {
+    $container = (new Container())->createContainer();
+    $callback($container);
+    $container->compile();
+    Container::useContainer($container);
+  }
+
+}
+
+class HookStyleServiceListenerTestExample implements HookInterface {
+
+  /**
+   * Free-form list of strings.
+   *
+   * @var array
+   */
+  public static $notes = [];
+
+  public function __construct($rand) {
+    self::$notes[] = "construct($rand)";
+  }
+
+  public function hook_civicrm_hssvlt(&$foo) {
+    self::$notes[] = "fired({$foo})";
+    $foo++;
+  }
+
+}