Adds the InvokableFactory

Most of the component refactors are complete, and will need to be re-done.
However, one item that should likely be retained is usage of the `InvokableFactory`
for invokable instances. This patch adds that factory to the v2 series,
having it implement `Zend\ServiceManager\FactoryInterface`, but retaining the
defined invokable method from v3. It raises an exception if the `$requestedName`
is not provided, ensuring that any tests against the functionality are using
a `ServiceManager` instance.

src/Factory/InvokableFactory.php

@@ -0,0 +1,67 @@
+<?php
+/**
+ * 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)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace Zend\ServiceManager\Factory;
+
+use Interop\Container\ContainerInterface;
+use Zend\ServiceManager\Exception\InvalidServiceNameException;
+use Zend\ServiceManager\FactoryInterface;
+use Zend\ServiceManager\ServiceLocatorInterface;
+
+/**
+ * Factory for instantiating classes with no dependencies or which accept a single array.
+ *
+ * The InvokableFactory can be used for any class that:
+ *
+ * - has no constructor arguments;
+ * - accepts a single array of arguments via the constructor.
+ *
+ * It replaces the "invokables" and "invokable class" functionality of the v2
+ * service manager, and can also be used in v2 code for forwards compatibility
+ * with v3.
+ */
+final class InvokableFactory implements FactoryInterface
+{
+    /**
+     * Create an instance of the requested class name.
+     *
+     * @param ContainerInterface $container
+     * @param string $requestedName
+     * @param null|array $options
+     * @return object
+     */
+    public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
+    {
+        return (null === $options) ? new $requestedName : new $requestedName($options);
+    }
+
+    /**
+     * Create an instance of the named service.
+     *
+     * If `$requestedName` is not provided, raises an exception; otherwise,
+     * proxies to the `__invoke()` method to create an instance of the
+     * requested class.
+     *
+     * @param ServiceLocatorInterface $serviceLocator
+     * @param null|string $canonicalName Ignored
+     * @param null|string $requestedName
+     * @return object
+     * @throws InvalidServiceNameException
+     */
+    public function createService(ServiceLocatorInterface $serviceLocator, $canonicalName = null, $requestedName = null)
+    {
+        if (! $requestedName) {
+            throw new InvalidServiceNameException(sprintf(
+                '%s requires that the requested name is provided on invocation; please update your tests or consuming container',
+                __CLASS__
+            ));
+        }
+        return $this($serviceLocator, $requestedName);
+    }
+}

test/Factory/InvokableFactoryTest.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * 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)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace ZendTest\ServiceManager\Factory;
+
+use Interop\Container\ContainerInterface;
+use PHPUnit_Framework_TestCase as TestCase;
+use Zend\ServiceManager\Factory\InvokableFactory;
+use ZendTest\ServiceManager\TestAsset\InvokableObject;
+
+/**
+ * @covers \Zend\ServiceManager\Factory\InvokableFactory
+ */
+class InvokableFactoryTest extends TestCase
+{
+    public function testCanCreateObject()
+    {
+        $container = $this->getMock(ContainerInterface::class);
+        $factory   = new InvokableFactory();
+
+        $object = $factory($container, InvokableObject::class, ['foo' => 'bar']);
+
+        $this->assertInstanceOf(InvokableObject::class, $object);
+        $this->assertEquals(['foo' => 'bar'], $object->options);
+    }
+}

test/TestAsset/InvokableObject.php

@@ -0,0 +1,34 @@
+<?php
+/**
+ * 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)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace ZendTest\ServiceManager\TestAsset;
+
+class InvokableObject
+{
+    /**
+     * @var array
+     */
+    public $options;
+
+    /**
+     * @param array $options
+     */
+    public function __construct(array $options = [])
+    {
+        $this->options = $options;
+    }
+
+    /**
+     * @return array
+     */
+    public function getOptions()
+    {
+        return $this->options;
+    }
+}