ensure log dispatcher gets registered with logger in all cases

fixes #2894

framework/log/Dispatcher.php

@@ -78,7 +78,7 @@ class Dispatcher extends Component
     public function __construct($config = [])
     {
         if (isset($config['logger'])) {
-            $this->_logger = $config['logger'];
+            $this->setLogger($config['logger']);
             unset($config['logger']);
         }
         // connect logger and dispatcher
@@ -110,8 +110,7 @@ class Dispatcher extends Component
     public function getLogger()
     {
         if ($this->_logger === null) {
-            $this->_logger = Yii::getLogger();
-            $this->_logger->dispatcher = $this;
+            $this->setLogger(Yii::getLogger());
         }
         return $this->_logger;
     }
@@ -123,6 +122,7 @@ class Dispatcher extends Component
     public function setLogger($value)
     {
         $this->_logger = $value;
+        $this->_logger->dispatcher = $this;
     }
 
     /**

tests/unit/framework/log/LoggerTest.php

@@ -8,6 +8,9 @@ namespace yiiunit\framework\log;
 use yii\log\Logger;
 use yiiunit\TestCase;
 
+/**
+ * @group log
+ */
 class LoggerTest extends TestCase
 {
 

tests/unit/framework/log/TargetTest.php

@@ -10,6 +10,9 @@ use yii\log\Logger;
 use yii\log\Target;
 use yiiunit\TestCase;
 
+/**
+ * @group log
+ */
 class TargetTest extends TestCase
 {
     public static $messages;