Add void return to method in tests. (#20602)

tests/framework/web/session/CacheSessionTest.php

@@ -8,6 +8,7 @@
 
 namespace yiiunit\framework\web\session;
 
+use yiiunit\TestCase;
 use Yii;
 use yii\caching\FileCache;
 use yii\web\CacheSession;
@@ -15,7 +16,7 @@ use yii\web\CacheSession;
 /**
  * @group web
  */
-class CacheSessionTest extends \yiiunit\TestCase
+class CacheSessionTest extends TestCase
 {
     use SessionTestTrait;
 
@@ -26,7 +27,7 @@ class CacheSessionTest extends \yiiunit\TestCase
         Yii::$app->set('cache', new FileCache());
     }
 
-    public function testCacheSession()
+    public function testCacheSession(): void
     {
         $session = new CacheSession();
 
@@ -36,7 +37,7 @@ class CacheSessionTest extends \yiiunit\TestCase
         $this->assertEquals('', $session->readSession('test'));
     }
 
-    public function testInvalidCache()
+    public function testInvalidCache(): void
     {
         $this->expectException('\Exception');
         new CacheSession(['cache' => 'invalid']);
@@ -45,7 +46,7 @@ class CacheSessionTest extends \yiiunit\TestCase
     /**
      * @see https://github.com/yiisoft/yii2/issues/13537
      */
-    public function testNotWrittenSessionDestroying()
+    public function testNotWrittenSessionDestroying(): void
     {
         $session = new CacheSession();
 
@@ -55,12 +56,12 @@ class CacheSessionTest extends \yiiunit\TestCase
         $this->assertTrue($session->destroySession($session->getId()));
     }
 
-    public function testInitUseStrictMode()
+    public function testInitUseStrictMode(): void
     {
         $this->initStrictModeTest(CacheSession::className());
     }
 
-    public function testUseStrictMode()
+    public function testUseStrictMode(): void
     {
         $this->useStrictModeTest(CacheSession::className());
     }