Add accessor for extension classes

Author: dantleech

lib/Container.php

@@ -271,4 +271,12 @@ public function hasParameter($name)
     {
         return array_key_exists($name, $this->config);
     }
+
+    /**
+     * @return class-string[]
+     */
+    public function getExtensionClasses(): array
+    {
+        return $this->extensionClasses;
+    }
 }

tests/Unit/ContainerTest.php

@@ -110,6 +110,9 @@ public function testRegisterExtension()
         $object = $container->get('foobar');
         $this->assertInstanceOf('stdClass', $object);
         $this->assertEquals('bar', $object->foobar);
+        $this->assertEquals([
+            __NAMESPACE__ . '\\TestExtension',
+        ], $container->getExtensionClasses());;
     }
 
     /**