diff --git a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
index 249ce85..4fd66fd 100644
--- a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
@@ -53,8 +53,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style);
         $registeredStyles = $styleHelper->registerStyle($style);
 
-        $this->assertEquals(1, $registeredStyles[0]->getId());
-        $this->assertEquals(2, $registeredStyles[1]->getId());
+        $this->assertEquals(0, $registeredStyles[0]->getId());
+        $this->assertEquals(1, $registeredStyles[1]->getId());
         $this->assertEquals(2, count($registeredStyles));
     }
 
diff --git a/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php b/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
index b608f16..806765a 100644
--- a/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
@@ -38,8 +38,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style1);
         $registeredStyles = $styleHelper->registerStyle($style2);
 
-        $this->assertEquals(1, $registeredStyles[0]->getId());
-        $this->assertEquals(2, $registeredStyles[1]->getId());
+        $this->assertEquals(1, $registeredStyles[1]->getId());
+        $this->assertEquals(2, $registeredStyles[2]->getId());
     }
 
     /**
@@ -53,8 +53,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style);
         $registeredStyles = $styleHelper->registerStyle($style);
 
-        $this->assertEquals(1, $registeredStyles[0]->getId());
-        $this->assertEquals(2, $registeredStyles[1]->getId());
+        $this->assertEquals(0, $registeredStyles[0]->getId());
+        $this->assertEquals(1, $registeredStyles[1]->getId());
         $this->assertEquals(2, count($registeredStyles));
     }