Adam G-H
--- a/tests/src/Kernel/ReadinessValidation/PendingUpdatesValidatorTest.php → package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php
+++ b/tests/src/Kernel/ReadinessValidation/PendingUpdatesValidatorTest.php → package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php
+  protected static $modules = ['package_manager'];
+
+  /**
+   * Runs the validator under test, and asserts its results match expectations.
+   *
+   * @param \Drupal\package_manager\ValidationResult[] $expected_results
+   *   The expected validation results.
+   */
+  private function assertResults(array $expected_results): void {
+    $stage = $this->prophesize('\Drupal\package_manager\Stage');
+    $event = new PreCreateEvent($stage->reveal());
+    $this->container->get('package_manager.validator.pending_updates')
+      ->validateStage($event);
+
+    $this->assertValidationResultsEqual($expected_results, $event->getResults());
+  }