class ServiceDestructionTest

class ServiceDestructionTest extends KernelTestBase {
  
  /**
   * Verifies that services are destructed when used.
   */
  public function testDestructionUsed() {
    // Enable the test module to add it to the container.
    $this->enableModules([
      'service_provider_test',
    ]);
    $request = $this->container
      ->get('request_stack')
      ->getCurrentRequest();
    $kernel = $this->container
      ->get('kernel');
    $kernel->preHandle($request);
    // The service has not been destructed yet.
    $this->assertNull(\Drupal::state()->get('service_provider_test.destructed'));
    // Call the class and then terminate the kernel
    $this->container
      ->get('service_provider_test_class');
    $response = new Response();
    $kernel->terminate($request, $response);
    $this->assertTrue(\Drupal::state()->get('service_provider_test.destructed'));
  }
  
  /**
   * Verifies that services are not unnecessarily destructed when not used.
   */
  public function testDestructionUnused() {
    // Enable the test module to add it to the container.
    $this->enableModules([
      'service_provider_test',
    ]);
    $request = $this->container
      ->get('request_stack')
      ->getCurrentRequest();
    $kernel = $this->container
      ->get('kernel');
    $kernel->preHandle($request);
    // The service has not been destructed yet.
    $this->assertNull(\Drupal::state()->get('service_provider_test.destructed'));
    // Terminate the kernel. The test class has not been called, so it should not
    // be destructed.
    $response = new Response();
    $kernel->terminate($request, $response);
    $this->assertNull(\Drupal::state()->get('service_provider_test.destructed'));
  }

}