diff --git a/tests/Functional/EstV3PosTest.php b/tests/Functional/EstV3PosTest.php
index 0be4dc8b..f50edc19 100644
--- a/tests/Functional/EstV3PosTest.php
+++ b/tests/Functional/EstV3PosTest.php
@@ -81,7 +81,7 @@ function (RequestDataPreparedEvent $requestDataPreparedEvent) use (&$eventIsThro
         );
 
         $response = $this->pos->getResponse();
-        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? null);
+        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? '');
 
         $this->assertIsArray($response);
         $this->assertNotEmpty($response);
@@ -208,7 +208,7 @@ function (RequestDataPreparedEvent $requestDataPreparedEvent) use (&$eventIsThro
         );
 
         $response = $this->pos->getResponse();
-        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? null);
+        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? '');
 
         $this->assertIsArray($response);
         $this->assertNotEmpty($response);
diff --git a/tests/Functional/GarantiPosTest.php b/tests/Functional/GarantiPosTest.php
index 82c7771b..65f6c24a 100644
--- a/tests/Functional/GarantiPosTest.php
+++ b/tests/Functional/GarantiPosTest.php
@@ -139,8 +139,8 @@ function (RequestDataPreparedEvent $requestDataPreparedEvent) use (&$eventIsThro
 
         $this->pos->cancel($statusOrder);
 
-        $this->assertTrue($this->pos->isSuccess());
         $response = $this->pos->getResponse();
+        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? '');
         $this->assertIsArray($response);
         $this->assertNotEmpty($response);
         $this->assertTrue($eventIsThrown);
@@ -171,9 +171,9 @@ function (RequestDataPreparedEvent $requestDataPreparedEvent) use (&$eventIsThro
             $this->card
         );
 
-        $this->assertTrue($this->pos->isSuccess());
-
         $response = $this->pos->getResponse();
+        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? '');
+
         $this->assertIsArray($response);
         $this->assertNotEmpty($response);
         $this->assertTrue($eventIsThrown);
diff --git a/tests/Functional/PayForPosTest.php b/tests/Functional/PayForPosTest.php
index 42bb67ec..e72d60e8 100644
--- a/tests/Functional/PayForPosTest.php
+++ b/tests/Functional/PayForPosTest.php
@@ -135,8 +135,8 @@ function (RequestDataPreparedEvent $requestDataPreparedEvent) use (&$eventIsThro
 
         $this->pos->cancel($statusOrder);
 
-        $this->assertTrue($this->pos->isSuccess());
         $response = $this->pos->getResponse();
+        $this->assertTrue($this->pos->isSuccess(), $response['error_message'] ?? '');
         $this->assertIsArray($response);
         $this->assertNotEmpty($response);
         $this->assertTrue($eventIsThrown);