Ensure input filter plugin manager is BC with v2

- Renamed `MigrationTest` to `InputFilterPluginManagerCompatibilityTest`
  (consistency with other components, and this is specifically for
  testing migration of the plugin manager).
- Added tests to validate that the `InputFilterPluginManager` accepts no
  arguments and/or a `ConfigInterface` argument to the constructor when
  using zend-servicemanager v2.
- Updated the `InputFilterPluginManager` constructor to mirror that of
  the 2.7 and 3.0 series of zend-servicemanager; it also populates the
  initializers prior to calling the parent constructor, allowing
  overriding.

src/InputFilterPluginManager.php

@@ -62,15 +62,16 @@ class InputFilterPluginManager extends AbstractPluginManager
      */
     protected $shareByDefault = false;
 
-
     /**
-     * @param ContainerInterface $parentLocator
-     * @param array $config
+     * @param null|\Zend\ServiceManager\ConfigInterface|ContainerInterface $configOrContainer
+     *     For zend-servicemanager v2, null or a ConfigInterface instance are
+     *     allowed; for v3, a ContainerInterface is expected.
+     * @param array $v3config Optional configuration array (zend-servicemanager v3 only)
      */
-    public function __construct(ContainerInterface $parentLocator, array $config = [])
+    public function __construct($configOrContainer = null, array $v3config = [])
     {
-        parent::__construct($parentLocator, $config);
-        $this->addInitializer([$this, 'populateFactory']);
+        $this->initializers[] = [$this, 'populateFactory'];
+        parent::__construct($configOrContainer, $v3config);
     }
 
     /**

test/MigrationTest.php → test/InputFilterPluginManagerCompatibilityTest.php

@@ -12,10 +12,11 @@
 use PHPUnit_Framework_TestCase as TestCase;
 use Zend\InputFilter\Exception\RuntimeException;
 use Zend\InputFilter\InputFilterPluginManager;
+use Zend\ServiceManager\Config;
 use Zend\ServiceManager\ServiceManager;
 use Zend\ServiceManager\Test\CommonPluginManagerTrait;
 
-class MigrationTest extends TestCase
+class InputFilterPluginManagerCompatibilityTest extends TestCase
 {
     use CommonPluginManagerTrait;
 
@@ -39,4 +40,26 @@ protected function getInstanceOf()
         // InputFilterManager accepts multiple instance types
         return;
     }
+
+    public function testConstructorArgumentsAreOptionalUnderV2()
+    {
+        $plugins = $this->getPluginManager();
+        if (method_exists($plugins, 'configure')) {
+            $this->markTestSkipped('zend-servicemanager v3 plugin managers require a container argument');
+        }
+
+        $plugins = new InputFilterPluginManager();
+        $this->assertInstanceOf(InputFilterPluginManager::class, $plugins);
+    }
+
+    public function testConstructorAllowsConfigInstanceAsFirstArgumentUnderV2()
+    {
+        $plugins = $this->getPluginManager();
+        if (method_exists($plugins, 'configure')) {
+            $this->markTestSkipped('zend-servicemanager v3 plugin managers require a container argument');
+        }
+
+        $plugins = new InputFilterPluginManager(new Config([]));
+        $this->assertInstanceOf(InputFilterPluginManager::class, $plugins);
+    }
 }