diff --git a/src/Spout/Common/Helper/GlobalFunctionsHelper.php b/src/Spout/Common/Helper/GlobalFunctionsHelper.php
index 550a6b1..eb02c3f 100644
--- a/src/Spout/Common/Helper/GlobalFunctionsHelper.php
+++ b/src/Spout/Common/Helper/GlobalFunctionsHelper.php
@@ -91,6 +91,21 @@ class GlobalFunctionsHelper
         return fgetcsv($handle, $length, $delimiter, $enclosure);
     }
 
+    /**
+     * Wrapper around global function fputcsv()
+     * @see fputcsv()
+     *
+     * @param resource $handle
+     * @param array $fields
+     * @param string|void $delimiter
+     * @param string|void $enclosure
+     * @return int
+     */
+    public function fputcsv($handle, array $fields, $delimiter = null, $enclosure = null)
+    {
+        return fputcsv($handle, $fields, $delimiter, $enclosure);
+    }
+
     /**
      * Wrapper around global function fclose()
      * @see fclose()
diff --git a/src/Spout/Writer/CSV.php b/src/Spout/Writer/CSV.php
index 0ac8d91..59e37a7 100644
--- a/src/Spout/Writer/CSV.php
+++ b/src/Spout/Writer/CSV.php
@@ -73,7 +73,7 @@ class CSV extends AbstractWriter
      */
     protected function addRowToWriter(array $dataRow)
     {
-        $wasWriteSuccessful = fputcsv($this->filePointer, $dataRow, $this->fieldDelimiter, $this->fieldEnclosure);
+        $wasWriteSuccessful = $this->globalFunctionsHelper->fputcsv($this->filePointer, $dataRow, $this->fieldDelimiter, $this->fieldEnclosure);
         if ($wasWriteSuccessful === false) {
             throw new IOException('Unable to write data');
         }
diff --git a/tests/Spout/Reader/XLSXTest.php b/tests/Spout/Reader/XLSXTest.php
index 3a1a34f..18586d5 100644
--- a/tests/Spout/Reader/XLSXTest.php
+++ b/tests/Spout/Reader/XLSXTest.php
@@ -38,6 +38,37 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
         $this->getAllRowsForFile($filePath);
     }
 
+    /**
+     * @expectedException \Box\Spout\Reader\Exception\ReaderNotOpenedException
+     *
+     * @return void
+     */
+    public function testHasNextSheetShouldThrowExceptionIfReaderNotOpened()
+    {
+        $reader = ReaderFactory::create(Type::XLSX);
+        $reader->hasNextSheet();
+    }
+
+    /**
+     * @expectedException \Box\Spout\Reader\Exception\EndOfWorksheetsReachedException
+     *
+     * @return void
+     */
+    public function testNextSheetShouldThrowExceptionIfNoMoreSheetsToRead()
+    {
+        $fileName = 'one_sheet_with_shared_strings.xlsx';
+        $resourcePath = $this->getResourcePath($fileName);
+
+        $reader = ReaderFactory::create(Type::XLSX);
+        $reader->open($resourcePath);
+
+        while ($reader->hasNextSheet()) {
+            $reader->nextSheet();
+        }
+
+        $reader->nextSheet();
+    }
+
     /**
      * @return array
      */