Added missing models for Redis tests

tests/unit/data/ar/redis/OrderItemWithNullFK.php

+<?php
+
+namespace yiiunit\data\ar\redis;
+
+/**
+ * Class OrderItem
+ *
+ * @property integer $order_id
+ * @property integer $item_id
+ * @property integer $quantity
+ * @property string $subtotal
+ */
+class OrderItemWithNullFK extends ActiveRecord
+{
+    public static function primaryKey()
+    {
+        return ['order_id', 'item_id'];
+    }
+
+    public function attributes()
+    {
+        return ['order_id', 'item_id', 'quantity', 'subtotal'];
+    }
+}

tests/unit/data/ar/redis/OrderWithNullFK.php

+<?php
+
+namespace yiiunit\data\ar\redis;
+
+/**
+ * Class Order
+ *
+ * @property integer $id
+ * @property integer $customer_id
+ * @property integer $created_at
+ * @property string $total
+ */
+class OrderWithNullFK extends ActiveRecord
+{
+    public static function primaryKey()
+    {
+        return ['id'];
+    }
+
+    public function attributes()
+    {
+        return ['id', 'customer_id', 'created_at', 'total'];
+    }
+}

tests/unit/extensions/redis/ActiveRecordTest.php

@@ -8,6 +8,8 @@ use yiiunit\data\ar\redis\Customer;
 use yiiunit\data\ar\redis\OrderItem;
 use yiiunit\data\ar\redis\Order;
 use yiiunit\data\ar\redis\Item;
+use yiiunit\data\ar\redis\OrderItemWithNullFK;
+use yiiunit\data\ar\redis\OrderWithNullFK;
 use yiiunit\framework\ar\ActiveRecordTestTrait;
 
 /**
@@ -37,6 +39,16 @@ class ActiveRecordTest extends RedisTestCase
         return OrderItem::className();
     }
 
+    public function getOrderWithNullFKClass()
+    {
+        return OrderWithNullFK::className();
+    }
+
+    public function getOrderItemWithNullFKmClass()
+    {
+        return OrderItemWithNullFK::className();
+    }
+
     public function setUp()
     {
         parent::setUp();