diff --git a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
index 46a73e7..c24bd75 100644
--- a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
@@ -53,8 +53,9 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style);
         $registeredStyles = $styleHelper->registerStyle($style);
 
-        $this->assertEquals(1, $registeredStyles[0]->getId());
-        $this->assertEquals(1, $registeredStyles[0]->getId());
+        $this->assertEquals(1, $registeredStyles[1]->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 cc59fbb..5b88063 100644
--- a/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
@@ -53,8 +53,9 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style);
         $registeredStyles = $styleHelper->registerStyle($style);
 
-        $this->assertEquals(1, $registeredStyle1->getId());
-        $this->assertEquals(1, $registeredStyle2->getId());
+        $this->assertEquals(1, $registeredStyles[0]->getId());
+        $this->assertEquals(1, $registeredStyles[0]->getId());
+        $this->assertEquals(2, count($registeredStyles));
     }
 
     /**