diff --git a/tests/Fixtures/session/common.php b/tests/Fixtures/session/common.php
index 9206967b5e0..87c0d38e84b 100644
--- a/tests/Fixtures/session/common.php
+++ b/tests/Fixtures/session/common.php
@@ -74,10 +74,12 @@
 class MockSessionHandler extends \SessionHandler
 {
     private $data;
+    private $sessionId;
 
-    public function __construct($data = null)
+    public function __construct($data = '', $sessionId = null)
     {
         $this->data = $data;
+        $this->sessionId = $sessionId;
     }
 
     public function getData()
@@ -173,7 +175,13 @@ public function gc($maxLifetime)
 
     protected function doRead($sessionId)
     {
+        if (isset($this->sessionId) && $sessionId !== $this->sessionId) {
+            echo __FUNCTION__ . ": invalid sessionId\n";
+
+            return '';
+        }
         echo __FUNCTION__.': ', $this->data, "\n";
+        $this->sessionId = $sessionId;
 
         return $this->data;
     }
@@ -181,6 +189,7 @@ protected function doRead($sessionId)
     protected function doWrite($sessionId, $data)
     {
         echo __FUNCTION__.': ', $data, "\n";
+        $this->sessionId = $sessionId;
 
         return true;
     }
@@ -188,6 +197,7 @@ protected function doWrite($sessionId, $data)
     protected function doDestroy($sessionId)
     {
         echo __FUNCTION__, "\n";
+        $this->sessionId = $sessionId;
 
         return true;
     }
diff --git a/tests/Fixtures/session/regenerate.expected b/tests/Fixtures/session/regenerate.expected
index bd166b81ef3..c777a58e486 100644
--- a/tests/Fixtures/session/regenerate.expected
+++ b/tests/Fixtures/session/regenerate.expected
@@ -9,9 +9,8 @@ close
 open
 validateId
 read
-doRead: abc|i:123;
+doRead: invalid sessionId
 read
-doRead: abc|i:123;
 
 write
 doWrite: abc|i:123;
diff --git a/tests/Fixtures/session/regenerate.samesite.expected b/tests/Fixtures/session/regenerate.samesite.expected
index b004cc2d826..ead311e3c49 100644
--- a/tests/Fixtures/session/regenerate.samesite.expected
+++ b/tests/Fixtures/session/regenerate.samesite.expected
@@ -9,9 +9,8 @@ close
 open
 validateId
 read
-doRead: abc|i:123;
+doRead: invalid sessionId
 read
-doRead: abc|i:123;
 
 write
 doWrite: abc|i:123;
diff --git a/tests/Fixtures/session/regenerate.secure.expected b/tests/Fixtures/session/regenerate.secure.expected
index d825f44f7cb..95c96f0cccd 100644
--- a/tests/Fixtures/session/regenerate.secure.expected
+++ b/tests/Fixtures/session/regenerate.secure.expected
@@ -9,9 +9,8 @@ close
 open
 validateId
 read
-doRead: abc|i:123;
+doRead: invalid sessionId
 read
-doRead: abc|i:123;
 
 write
 doWrite: abc|i:123;