diff --git a/src/ConcurrentAssignmentsStorageDecorator.php b/src/ConcurrentAssignmentsStorageDecorator.php
index b8d3490..7528ac6 100644
--- a/src/ConcurrentAssignmentsStorageDecorator.php
+++ b/src/ConcurrentAssignmentsStorageDecorator.php
@@ -71,6 +71,7 @@ public function add(Assignment $assignment): void
     {
         $this->load();
         $this->storage->add($assignment);
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function hasItem(string $name): bool
@@ -84,38 +85,38 @@ public function renameItem(string $oldName, string $newName): void
     {
         $this->load();
         $this->storage->renameItem($oldName, $newName);
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function remove(string $itemName, string $userId): void
     {
         $this->load();
         $this->storage->remove($itemName, $userId);
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function removeByUserId(string $userId): void
     {
         $this->load();
         $this->storage->removeByUserId($userId);
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function removeByItemName(string $itemName): void
     {
         $this->load();
         $this->storage->removeByItemName($itemName);
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function clear(): void
     {
         $this->storage->clear();
+        $this->currentFileUpdatedAt = $this->getFileUpdatedAt();
     }
 
     public function load(): void
     {
         $this->loadInternal($this->storage);
     }
-
-    public function getFileUpdatedAt(): int
-    {
-        return $this->storage->getFileUpdatedAt();
-    }
 }
diff --git a/tests/AssignmentsStorageTest.php b/tests/AssignmentsStorageTest.php
new file mode 100644
index 0000000..e9f1e7d
--- /dev/null
+++ b/tests/AssignmentsStorageTest.php
@@ -0,0 +1,170 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Rbac\Php\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Rbac\Assignment;
+use Yiisoft\Rbac\AssignmentsStorageInterface;
+use Yiisoft\Rbac\ItemsStorageInterface;
+use Yiisoft\Rbac\Php\AssignmentsStorage;
+use Yiisoft\Rbac\Php\ConcurrentAssignmentsStorageDecorator;
+use Yiisoft\Rbac\Php\ConcurrentItemsStorageDecorator;
+use Yiisoft\Rbac\Php\ItemsStorage;
+use Yiisoft\Rbac\Tests\Common\AssignmentsStorageTestTrait;
+
+final class AssignmentsStorageTest extends TestCase
+{
+    use AssignmentsStorageTestTrait {
+        setUp as protected traitSetUp;
+    }
+    use StorageFilePathTrait;
+
+    protected function setUp(): void
+    {
+        $this->traitSetUp();
+    }
+
+    protected function tearDown(): void
+    {
+        $this->clearFixturesFiles();
+    }
+
+    public function testGetAllWithConcurrency(): void
+    {
+        $this->assertNotEmpty($this->getEmptyConcurrentAssignmentsStorage()->getAll());
+    }
+
+    public function testGetByUserIdWithConcurrency(): void
+    {
+        $this->assertNotEmpty($this->getEmptyConcurrentAssignmentsStorage()->getByUserId('john'));
+    }
+
+    public function testGetByItemNamesWithConcurrency(): void
+    {
+        $this->assertNotEmpty($this->getEmptyConcurrentAssignmentsStorage()->getByItemNames(['Researcher']));
+    }
+
+    public function testGetWithConcurrency(): void
+    {
+        $this->assertNotEmpty($this->getEmptyConcurrentAssignmentsStorage()->get(itemName: 'Researcher', userId: 'john'));
+    }
+
+    public function testExistsWithConcurrency(): void
+    {
+        $this->assertTrue(
+            $this->getEmptyConcurrentAssignmentsStorage()->exists(itemName: 'Researcher', userId: 'john'),
+        );
+    }
+
+    public function testUserHasItemWithConcurrency(): void
+    {
+        $this->assertTrue(
+            $this->getEmptyConcurrentAssignmentsStorage()->userHasItem(userId: 'john', itemNames: ['Researcher']),
+        );
+    }
+
+    public function testFilterUserItemNamesWithConcurrency(): void
+    {
+        $this->assertNotEmpty(
+            $this->getEmptyConcurrentAssignmentsStorage()->filterUserItemNames(
+                userId: 'john',
+                itemNames: ['Researcher'],
+            ),
+        );
+    }
+
+    public function testAddWithConcurrency(): void
+    {
+        $testStorage = new AssignmentsStorage($this->getDataPath());
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $time = time();
+        $actionStorage->add(new Assignment(userId: 'jack', itemName: 'Researcher', createdAt: $time));
+        $count = count($actionStorage->getByItemNames(['Researcher']));
+        $actionStorage->add(new Assignment(userId: 'jeff', itemName: 'Researcher', createdAt: $time));
+
+        $testStorage->add(new Assignment(userId: 'jack', itemName: 'Researcher', createdAt: $time));
+        $this->assertCount($count, $testStorage->getByItemNames(['Researcher']));
+    }
+
+    public function testHasItemWithConcurrency(): void
+    {
+        $this->assertTrue($this->getEmptyConcurrentAssignmentsStorage()->hasItem('Researcher'));
+    }
+
+    public function testRenameItemWithConcurrency(): void
+    {
+        $testStorage = new AssignmentsStorage($this->getDataPath());
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->renameItem('Researcher', 'Researcher1');
+        $actionStorage->renameItem('Accountant', 'Accountant1');
+
+        $testStorage->renameItem('Researcher', 'Researcher1');
+        $this->assertFalse($testStorage->hasItem('Accountant1'));
+    }
+
+    public function testRemoveWithConcurrency(): void
+    {
+        $testStorage = new AssignmentsStorage($this->getDataPath());
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->remove(itemName: 'Researcher', userId: 'john');
+        $count = count($actionStorage->getByUserId('john'));
+        $actionStorage->remove(itemName: 'Accountant', userId: 'john');
+
+        $testStorage->remove(itemName: 'Researcher', userId: 'john');
+        $this->assertCount($count, $testStorage->getByUserId('john'));
+    }
+
+    public function testRemoveByUserIdWithConcurrency(): void
+    {
+        $testStorage = new AssignmentsStorage($this->getDataPath());
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->removeByUserId('john');
+        $actionStorage->removeByUserId('jack');
+
+        $testStorage->removeByUserId('john');
+        $this->assertNotEmpty($testStorage->getByUserId('jack'));
+    }
+
+    public function testRemoveByItemNameWithConcurrency(): void
+    {
+        $testStorage = new AssignmentsStorage($this->getDataPath());
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->removeByItemName('Researcher');
+        $actionStorage->removeByItemName('Accountant');
+
+        $testStorage->removeByItemName('Researcher');
+        $this->assertNotEmpty($testStorage->getByItemNames(['Accountant']));
+    }
+
+    protected function createItemsStorage(): ItemsStorageInterface
+    {
+        return new ItemsStorage($this->getDataPath());
+    }
+
+    protected function createAssignmentsStorage(): AssignmentsStorageInterface
+    {
+        return new AssignmentsStorage($this->getDataPath());
+    }
+
+    protected function getAssignmentsStorageForModificationAssertions(): AssignmentsStorageInterface
+    {
+        return str_ends_with($this->name(), 'WithConcurrency')
+            ? $this->createAssignmentsStorage()
+            : $this->getAssignmentsStorage();
+    }
+
+    private function getEmptyConcurrentAssignmentsStorage(): AssignmentsStorageInterface
+    {
+        $storage = $this->getAssignmentsStorageForModificationAssertions();
+        $this->getAssignmentsStorage()->clear();
+
+        return $storage;
+    }
+}
diff --git a/tests/AssignmentsStorageWithConcurenncyHandlingTest.php b/tests/AssignmentsStorageWithConcurenncyHandlingTest.php
index 607cb99..5e08d7d 100644
--- a/tests/AssignmentsStorageWithConcurenncyHandlingTest.php
+++ b/tests/AssignmentsStorageWithConcurenncyHandlingTest.php
@@ -5,6 +5,7 @@
 namespace Yiisoft\Rbac\Php\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Yiisoft\Rbac\Assignment;
 use Yiisoft\Rbac\AssignmentsStorageInterface;
 use Yiisoft\Rbac\ItemsStorageInterface;
 use Yiisoft\Rbac\Php\AssignmentsStorage;
@@ -74,13 +75,77 @@ public function testFilterUserItemNamesWithConcurrency(): void
         );
     }
 
+    public function testAddWithConcurrency(): void
+    {
+        $innerTestStorage = new AssignmentsStorage($this->getDataPath());
+        $testStorage = new ConcurrentAssignmentsStorageDecorator($innerTestStorage);
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $time = time();
+        $actionStorage->add(new Assignment(userId: 'jack', itemName: 'Researcher', createdAt: $time));
+        $actionStorage->add(new Assignment(userId: 'jeff', itemName: 'Researcher', createdAt: $time));
+        $count = count($actionStorage->getByItemNames(['Researcher']));
+
+        $testStorage->add(new Assignment(userId: 'jack', itemName: 'Researcher', createdAt: $time));
+        $this->assertCount($count, $innerTestStorage->getByItemNames(['Researcher']));
+    }
+
     public function testHasItemWithConcurrency(): void
     {
         $this->assertFalse($this->getEmptyConcurrentAssignmentsStorage()->hasItem('Researcher'));
     }
 
-    public function removeByItemName(string $itemName): void
+    public function testRenameItemWithConcurrency(): void
+    {
+        $innerTestStorage = new AssignmentsStorage($this->getDataPath());
+        $testStorage = new ConcurrentAssignmentsStorageDecorator($innerTestStorage);
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->renameItem('Researcher', 'Researcher1');
+        $actionStorage->renameItem('Accountant', 'Accountant1');
+
+        $testStorage->renameItem('Researcher', 'Researcher1');
+        $this->assertTrue($innerTestStorage->hasItem('Accountant1'));
+    }
+
+    public function testRemoveWithConcurrency(): void
+    {
+        $innerTestStorage = new AssignmentsStorage($this->getDataPath());
+        $testStorage = new ConcurrentAssignmentsStorageDecorator($innerTestStorage);
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->remove(itemName: 'Researcher', userId: 'john');
+        $actionStorage->remove(itemName: 'Accountant', userId: 'john');
+        $count = count($actionStorage->getByUserId('john'));
+
+        $testStorage->remove(itemName: 'Researcher', userId: 'john');
+        $this->assertCount($count, $innerTestStorage->getByUserId('john'));
+    }
+
+    public function testRemoveByUserIdWithConcurrency(): void
     {
+        $innerTestStorage = new AssignmentsStorage($this->getDataPath());
+        $testStorage = new ConcurrentAssignmentsStorageDecorator($innerTestStorage);
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->removeByUserId('john');
+        $actionStorage->removeByUserId('jack');
+
+        $testStorage->removeByUserId('john');
+        $this->assertEmpty($innerTestStorage->getByUserId('jack'));
+    }
+
+    public function testRemoveByItemNameWithConcurrency(): void
+    {
+        $innerTestStorage = new AssignmentsStorage($this->getDataPath());
+        $testStorage = new ConcurrentAssignmentsStorageDecorator($innerTestStorage);
+        $actionStorage = $this->getAssignmentsStorage();
+
+        $actionStorage->removeByItemName('Researcher');
+        $actionStorage->removeByItemName('Accountant');
+
+        $testStorage->removeByItemName('Researcher');
+        $this->assertEmpty($innerTestStorage->getByItemNames(['Accountant']));
     }
 
     protected function createItemsStorage(): ItemsStorageInterface