add: regression test for increment method about expired cache

Author: zigzagdev

tests/Cache/MongoCacheStoreTest.php

@@ -199,6 +199,14 @@ public function testIncrementDecrement()
 
         $this->insertToCacheTable('foo', 10, -5);
         $this->assertFalse($store->increment('foo', 5));
+
+        $doc = DB::connection('mongodb')
+            ->getCollection($this->getCacheCollectionName())
+            ->findOne(
+                ['_id' => $this->withCachePrefix('foo')],
+                ['projection' => ['value' => 1]]
+            );
+        $this->assertSame(10, $doc['value']);
     }
 
     public function testTTLIndex()