diff --git a/tests/data/ar/Order.php b/tests/data/ar/Order.php
index 99b61ca..bff235f 100644
--- a/tests/data/ar/Order.php
+++ b/tests/data/ar/Order.php
@@ -180,7 +180,7 @@ class Order extends ActiveRecord
 
     public function getLimitedItems()
     {
-        return $this->hasMany(Item::className(), ['id' => 'item_id'])
+        return $this->hasMany(Item::class, ['id' => 'item_id'])
             ->onCondition(['item.id' => [3, 5]])
             ->via('orderItems');
     }
diff --git a/tests/framework/base/ApplicationTest.php b/tests/framework/base/ApplicationTest.php
index 37fc67e..9e9b24a 100644
--- a/tests/framework/base/ApplicationTest.php
+++ b/tests/framework/base/ApplicationTest.php
@@ -19,13 +19,13 @@ class ApplicationTest extends TestCase
         $this->mockApplication([
             'container' => [
                 'definitions' => [
-                    Dispatcher::className() => DispatcherMock::className()
+                    Dispatcher::class => DispatcherMock::class
                 ]
             ],
             'bootstrap' => ['log']
         ]);
 
-        $this->assertInstanceOf(DispatcherMock::className(), Yii::$app->log);
+        $this->assertInstanceOf(DispatcherMock::class, Yii::$app->log);
     }
 }
 
diff --git a/tests/framework/db/ActiveQueryTest.php b/tests/framework/db/ActiveQueryTest.php
index 777529c..7a0d860 100644
--- a/tests/framework/db/ActiveQueryTest.php
+++ b/tests/framework/db/ActiveQueryTest.php
@@ -134,7 +134,7 @@ abstract class ActiveQueryTest extends DatabaseTestCase
      */
     public function testGetQueryTableName_from_not_set()
     {
-        $query = new ActiveQuery(Customer::className());
+        $query = new ActiveQuery(Customer::class);
         $result = $this->invokeMethod($query,'getTableNameAndAlias');
         $this->assertEquals(['customer','customer'], $result);
     }
@@ -142,7 +142,7 @@ abstract class ActiveQueryTest extends DatabaseTestCase
     public function testGetQueryTableName_from_set()
     {
         $options = ['from' => ['alias'=>'customer']];
-        $query = new ActiveQuery(Customer::className(),$options);
+        $query = new ActiveQuery(Customer::class,$options);
         $result = $this->invokeMethod($query,'getTableNameAndAlias');
         $this->assertEquals(['customer','alias'], $result);
     }
diff --git a/tests/framework/db/ActiveRecordTest.php b/tests/framework/db/ActiveRecordTest.php
index f3c4e32..26d9f0c 100644
--- a/tests/framework/db/ActiveRecordTest.php
+++ b/tests/framework/db/ActiveRecordTest.php
@@ -55,7 +55,7 @@ abstract class ActiveRecordTest extends DatabaseTestCase
 
     public function getCategoryClass()
     {
-        return Category::className();
+        return Category::class;
     }
 
     public function getOrderWithNullFKClass()
diff --git a/tests/framework/di/ContainerTest.php b/tests/framework/di/ContainerTest.php
index c0cd5e9..c138e19 100644
--- a/tests/framework/di/ContainerTest.php
+++ b/tests/framework/di/ContainerTest.php
@@ -231,8 +231,8 @@ class ContainerTest extends TestCase
     {
         $container = new Container();
         $container->setDefinitions([
-            'model.order' => Order::className(),
-            Cat::className() => Type::className(),
+            'model.order' => Order::class,
+            Cat::class => Type::class,
             'test\TraversableInterface' => [
                 ['class' => 'yiiunit\data\base\TraversableObject'],
                 [['item1', 'item2']]
@@ -243,8 +243,8 @@ class ContainerTest extends TestCase
         ]);
         $container->setDefinitions([]);
 
-        $this->assertInstanceOf(Order::className(), $container->get('model.order'));
-        $this->assertInstanceOf(Type::className(), $container->get(Cat::className()));
+        $this->assertInstanceOf(Order::class, $container->get('model.order'));
+        $this->assertInstanceOf(Type::class, $container->get(Cat::class));
 
         $traversable = $container->get('test\TraversableInterface');
         $this->assertInstanceOf('yiiunit\data\base\TraversableObject', $traversable);
@@ -257,7 +257,7 @@ class ContainerTest extends TestCase
     {
         $container = new Container();
         $container->setSingletons([
-            'model.order' => Order::className(),
+            'model.order' => Order::class,
             'test\TraversableInterface' => [
                 ['class' => 'yiiunit\data\base\TraversableObject'],
                 [['item1', 'item2']]
diff --git a/tests/framework/filters/PageCacheTest.php b/tests/framework/filters/PageCacheTest.php
index c23a797..839cd59 100644
--- a/tests/framework/filters/PageCacheTest.php
+++ b/tests/framework/filters/PageCacheTest.php
@@ -403,7 +403,7 @@ class PageCacheTest extends TestCase
                 'cache' => $cache = new ArrayCache(),
                 'view' => new View(),
                 'dependency' => [
-                    'class' => ExpressionDependency::className(),
+                    'class' => ExpressionDependency::class,
                     'expression' => 'Yii::$app->params[\'dependency\']',
                 ]
             ]);
diff --git a/tests/framework/grid/RadiobuttonColumnTest.php b/tests/framework/grid/RadiobuttonColumnTest.php
index c247bf4..e4ec791 100644
--- a/tests/framework/grid/RadiobuttonColumnTest.php
+++ b/tests/framework/grid/RadiobuttonColumnTest.php
@@ -76,7 +76,7 @@ class RadiobuttonColumnTest extends TestCase
             'options' => ['id' => 'radio-gridview'],
             'columns' => [
                 [
-                    'class' => RadioButtonColumn::className(),
+                    'class' => RadioButtonColumn::class,
                     'radioOptions' => function ($model) {
                         return [
                             'value' => $model['value'],
diff --git a/tests/framework/validators/ValidatorTest.php b/tests/framework/validators/ValidatorTest.php
index 5556249..912fbb1 100644
--- a/tests/framework/validators/ValidatorTest.php
+++ b/tests/framework/validators/ValidatorTest.php
@@ -188,7 +188,7 @@ class ValidatorTest extends TestCase
         $this->assertCount(3, $args);
         $this->assertEquals('val_attr_a', $args[0]);
         $this->assertEquals(['foo' => 'bar'], $args[1]);
-        $this->assertInstanceOf(InlineValidator::className(), $args[2]);
+        $this->assertInstanceOf(InlineValidator::class, $args[2]);
     }
 
     public function testClientValidateAttribute()
@@ -208,7 +208,7 @@ class ValidatorTest extends TestCase
         $this->assertCount(3, $args);
         $this->assertEquals('val_attr_a', $args[0]);
         $this->assertEquals(['foo' => 'bar'], $args[1]);
-        $this->assertInstanceOf(InlineValidator::className(), $args[2]);
+        $this->assertInstanceOf(InlineValidator::class, $args[2]);
     }
 
     public function testIsActive()
diff --git a/tests/framework/web/ErrorActionTest.php b/tests/framework/web/ErrorActionTest.php
index 3ec4337..7402032 100644
--- a/tests/framework/web/ErrorActionTest.php
+++ b/tests/framework/web/ErrorActionTest.php
@@ -22,7 +22,7 @@ class ErrorActionTest extends TestCase
         $this->mockApplication([
             'components' => [
                 'request' => [
-                    'class' => Request::className(),
+                    'class' => Request::class,
                 ],
             ],
         ]);
@@ -115,7 +115,7 @@ class TestController extends Controller
     {
         return [
             'error' => array_merge([
-                'class' => ErrorAction::className(),
+                'class' => ErrorAction::class,
                 'view' => '@yiiunit/data/views/error.php',
             ], $this->actionConfig),
         ];