Added test

Based on #1787 by @astax-t

tests/Mocks/InvocationStrategyTest.php

@@ -0,0 +1,39 @@
+<?php
+/**
+ * Slim Framework (http://slimframework.com)
+ *
+ * @link      https://github.com/slimphp/Slim
+ * @copyright Copyright (c) 2011-2016 Josh Lockhart
+ * @license   https://github.com/slimphp/Slim/blob/master/LICENSE.md (MIT License)
+ */
+namespace Slim\Tests\Mocks;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Slim\Interfaces\InvocationStrategyInterface;
+
+class InvocationStrategyTest implements InvocationStrategyInterface
+{
+    public static $LastCalledFor = null;
+
+    /**
+     * Invoke a route callable.
+     *
+     * @param callable $callable The callable to invoke using the strategy.
+     * @param ServerRequestInterface $request The request object.
+     * @param ResponseInterface $response The response object.
+     * @param array $routeArguments The route's placholder arguments
+     *
+     * @return ResponseInterface|string The response from the callable.
+     */
+    public function __invoke(
+        callable $callable,
+        ServerRequestInterface $request,
+        ResponseInterface $response,
+        array $routeArguments
+    ) {
+        static::$LastCalledFor = $callable;
+
+        return $response;
+    }
+}

tests/RouteTest.php

@@ -18,6 +18,7 @@
 use Slim\Http\Uri;
 use Slim\Route;
 use Slim\Tests\Mocks\CallableTest;
+use Slim\Tests\Mocks\InvocationStrategyTest;
 use Slim\Tests\Mocks\MiddlewareStub;
 
 class RouteTest extends \PHPUnit_Framework_TestCase
@@ -130,7 +131,6 @@ public function testRefinalizing()
     }
 
 
-
     public function testIdentifier()
     {
         $route = $this->routeFactory();
@@ -384,4 +384,28 @@ public function testInvokeWhenDisablingOutputBuffer()
         $output = ob_get_clean();
         $this->assertEquals('foo', $output);
     }
+
+    /**
+     * Ensure that `foundHandler` is called on actual callable
+     */
+    public function testInvokeDeferredCallable()
+    {
+        $container = new Container();
+        $container['CallableTest'] = new CallableTest;
+        $container['foundHandler'] = function () {
+            return new InvocationStrategyTest();
+        };
+
+        $route = new Route(['GET'], '/', 'CallableTest:toCall');
+        $route->setContainer($container);
+
+        $uri = Uri::createFromString('https://example.com:80');
+        $body = new Body(fopen('php://temp', 'r+'));
+        $request = new Request('GET', $uri, new Headers(), [], Environment::mock()->all(), $body);
+
+        $result = $route->callMiddlewareStack($request, new Response);
+
+        $this->assertInstanceOf('Slim\Http\Response', $result);
+        $this->assertEquals([$container['CallableTest'], 'toCall'], InvocationStrategyTest::$LastCalledFor);
+    }
 }