Try to use AuthenticationServiceInterface for the Identity helper

CHANGELOG.md

@@ -10,6 +10,12 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Changed
 
+- [#155](https://github.com/zendframework/zend-view/pull/155) modifies the `Zend\View\Helper\Service\IdentifyFactory` such that it will
+  now also look for the service `Zend\Authentication\AuthenticationServiceInterface`
+  if the service `Zend\Authentication\AuthenticationService` is not found. This
+  allows using a service named after the interface instead of the
+  implementation if desired.
+
 - [#158](https://github.com/zendframework/zend-view/pull/158) modifies how a `ViewModel` (and all extensions) is cloned; the `$variables`
   property, if it is an object, is now cloned as well to ensure changes in the
   new instance do not affect the current one.

doc/book/helpers/identity.md

@@ -4,7 +4,8 @@ The `Identity` helper allows retrieving the identity from the
 `AuthenticationService`.
 
 For the `Identity` helper to work, a `Zend\Authentication\AuthenticationService`
-name or alias must be defined and recognized by the `ServiceManager`.
+or `Zend\Authentication\AuthenticationServiceInterface` name or alias must be
+defined and recognized by the `ServiceManager`.
 
 `Identity` returns the identity discovered in the `AuthenticationService`, or
 `null` if no identity is available.
@@ -43,3 +44,6 @@ return [
     ],
 ];
 ```
+
+If that service is not registered, the plugin will then look for a service named
+`Zend\Authentication\AuthenticationServiceInterface`, and use that if found.

src/Helper/Service/IdentityFactory.php

@@ -3,13 +3,15 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2018 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
 namespace Zend\View\Helper\Service;
 
 use Interop\Container\ContainerInterface;
+use Zend\Authentication\AuthenticationService;
+use Zend\Authentication\AuthenticationServiceInterface;
 use Zend\ServiceManager\FactoryInterface;
 use Zend\ServiceManager\ServiceLocatorInterface;
 use Zend\View\Helper\Identity;
@@ -30,10 +32,13 @@ public function __invoke(ContainerInterface $container, $name, array $options =
         if (! method_exists($container, 'configure')) {
             $container = $container->getServiceLocator();
         }
+
         $helper = new Identity();
-        if ($container->has('Zend\Authentication\AuthenticationService')) {
-            $helper->setAuthenticationService($container->get('Zend\Authentication\AuthenticationService'));
+
+        if (null !== ($authenticationService = $this->discoverAuthenticationService($container))) {
+            $helper->setAuthenticationService($authenticationService);
         }
+
         return $helper;
     }
 
@@ -47,4 +52,18 @@ public function createService(ServiceLocatorInterface $serviceLocator, $rName =
     {
         return $this($serviceLocator, $cName);
     }
+
+    /**
+     * @return null|AuthenticationServiceInterface
+     */
+    private function discoverAuthenticationService(ContainerInterface $container)
+    {
+        if ($container->has(AuthenticationService::class)) {
+            return $container->get(AuthenticationService::class);
+        }
+
+        return $container->has(AuthenticationServiceInterface::class)
+            ? $container->get(AuthenticationServiceInterface::class)
+            : null;
+    }
 }

test/Helper/Service/IdentityFactoryTest.php

@@ -0,0 +1,67 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-view for the canonical source repository
+ * @copyright Copyright (c) 2018 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   https://github.com/zendframework/zend-view/blob/master/LICENSE.md New BSD License
+ */
+
+namespace ZendTest\View\Helper\Service;
+
+use PHPUnit\Framework\TestCase;
+use Zend\Authentication\AuthenticationService;
+use Zend\Authentication\AuthenticationServiceInterface;
+use Zend\ServiceManager\ServiceManager;
+use Zend\View\Helper\Identity;
+use Zend\View\Helper\Service\IdentityFactory;
+
+class IdentityFactoryTest extends TestCase
+{
+    public function testFactoryReturnsEmptyIdentityIfNoAuthenticationServicePresent()
+    {
+        $container = $this->prophesize(ServiceManager::class);
+        $container->has(AuthenticationService::class)->willReturn(false);
+        $container->get(AuthenticationService::class)->shouldNotBeCalled();
+        $container->has(AuthenticationServiceInterface::class)->willReturn(false);
+        $container->get(AuthenticationServiceInterface::class)->shouldNotBeCalled();
+
+        $factory = new IdentityFactory();
+        $plugin = $factory($container->reveal(), Identity::class);
+
+        $this->assertInstanceOf(Identity::class, $plugin);
+        $this->assertNull($plugin->getAuthenticationService());
+    }
+
+    public function testFactoryReturnsIdentityWithConfiguredAuthenticationServiceWhenPresent()
+    {
+        $container = $this->prophesize(ServiceManager::class);
+        $authentication = $this->prophesize(AuthenticationService::class);
+
+        $container->has(AuthenticationService::class)->willReturn(true);
+        $container->get(AuthenticationService::class)->will([$authentication, 'reveal']);
+        $container->has(AuthenticationServiceInterface::class)->willReturn(false);
+        $container->get(AuthenticationServiceInterface::class)->shouldNotBeCalled();
+
+        $factory = new IdentityFactory();
+        $plugin = $factory($container->reveal(), Identity::class);
+
+        $this->assertInstanceOf(Identity::class, $plugin);
+        $this->assertSame($authentication->reveal(), $plugin->getAuthenticationService());
+    }
+
+    public function testFactoryReturnsIdentityWithConfiguredAuthenticationServiceInterfaceWhenPresent()
+    {
+        $container = $this->prophesize(ServiceManager::class);
+        $authentication = $this->prophesize(AuthenticationServiceInterface::class);
+
+        $container->has(AuthenticationService::class)->willReturn(false);
+        $container->get(AuthenticationService::class)->shouldNotBeCalled();
+        $container->has(AuthenticationServiceInterface::class)->willReturn(true);
+        $container->get(AuthenticationServiceInterface::class)->will([$authentication, 'reveal']);
+
+        $factory = new IdentityFactory();
+        $plugin = $factory($container->reveal(), Identity::class);
+
+        $this->assertInstanceOf(Identity::class, $plugin);
+        $this->assertSame($authentication->reveal(), $plugin->getAuthenticationService());
+    }
+}