Add test and update doc

docs/using-di.md

@@ -84,11 +84,6 @@ final class User extends ActiveRecord
     {
         $this->factory = $factory;
     }
-
-    public function getMyService(): MyService
-    {
-        return $this->myService;
-    }
 }
 ```
 

tests/ActiveRecordTest.php

@@ -1032,6 +1032,19 @@ public function testWithFactoryInstanceRelation(): void
         $this->assertInstanceOf(CustomerWithFactory::class, $order->getCustomerWithFactoryInstance());
     }
 
+    public function testWithFactoryRelationWithoutFactory(): void
+    {
+        $this->checkFixture($this->db(), 'order');
+
+        $factory = $this->createFactory();
+
+        $orderQuery = new ActiveQuery($factory->create(OrderWithFactory::class)->withFactory($factory));
+        $order = $orderQuery->findOne(2);
+
+        $this->assertInstanceOf(OrderWithFactory::class, $order);
+        $this->assertInstanceOf(Customer::class, $order->getCustomer());
+    }
+
     public function testWithFactoryLazyRelation(): void
     {
         $this->checkFixture($this->db(), 'order');