diff --git a/tests/Models/NullStockLocationTest.php b/tests/Models/NullStockLocationTest.php
index 9d76f0f..3cd3625 100644
--- a/tests/Models/NullStockLocationTest.php
+++ b/tests/Models/NullStockLocationTest.php
@@ -37,7 +37,7 @@ final class NullStockLocationTest extends \PHPUnit\Framework\TestCase
     public function testId() : void
     {
         $null = new NullStockLocation(2);
-        self::assertEquals(2, $null->getId());
+        self::assertEquals(2, $null->id);
     }
 
     /**
diff --git a/tests/Models/NullStockShelfTest.php b/tests/Models/NullStockShelfTest.php
index f78e186..686a75c 100644
--- a/tests/Models/NullStockShelfTest.php
+++ b/tests/Models/NullStockShelfTest.php
@@ -37,7 +37,7 @@ final class NullStockShelfTest extends \PHPUnit\Framework\TestCase
     public function testId() : void
     {
         $null = new NullStockShelf(2);
-        self::assertEquals(2, $null->getId());
+        self::assertEquals(2, $null->id);
     }
 
     /**
diff --git a/tests/Models/NullStockTest.php b/tests/Models/NullStockTest.php
index 4f3ef20..6a14091 100644
--- a/tests/Models/NullStockTest.php
+++ b/tests/Models/NullStockTest.php
@@ -37,7 +37,7 @@ final class NullStockTest extends \PHPUnit\Framework\TestCase
     public function testId() : void
     {
         $null = new NullStock(2);
-        self::assertEquals(2, $null->getId());
+        self::assertEquals(2, $null->id);
     }
 
     /**