diff --git a/composer.json b/composer.json
index 0cfa7d15..189b5478 100644
--- a/composer.json
+++ b/composer.json
@@ -39,7 +39,7 @@
         "phpoffice/common": "^0.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "3.7.*",
+        "phpunit/phpunit": "4.8.*",
         "phpdocumentor/phpdocumentor":"2.*",
         "twig/twig":"1.27",
         "squizlabs/php_codesniffer": "1.*",
diff --git a/tests/PhpWord/PhpWordTest.php b/tests/PhpWord/PhpWordTest.php
index 459c67a0..a7684a48 100644
--- a/tests/PhpWord/PhpWordTest.php
+++ b/tests/PhpWord/PhpWordTest.php
@@ -152,6 +152,7 @@ class PhpWordTest extends \PHPUnit_Framework_TestCase
      */
     public function testSave()
     {
+        $this->setOutputCallback(function() {});
         $phpWord = new PhpWord();
         $section = $phpWord->addSection();
         $section->addText('Hello world!');
diff --git a/tests/PhpWord/Writer/ODTextTest.php b/tests/PhpWord/Writer/ODTextTest.php
index d79a9d42..f4c2078a 100644
--- a/tests/PhpWord/Writer/ODTextTest.php
+++ b/tests/PhpWord/Writer/ODTextTest.php
@@ -102,6 +102,7 @@ class ODTextTest extends \PHPUnit_Framework_TestCase
      */
     public function testSavePhpOutput()
     {
+        $this->setOutputCallback(function() {});
         $phpWord = new PhpWord();
         $section = $phpWord->addSection();
         $section->addText('Test');
diff --git a/tests/PhpWord/Writer/RTFTest.php b/tests/PhpWord/Writer/RTFTest.php
index 0b4f6b0f..cdf162e6 100644
--- a/tests/PhpWord/Writer/RTFTest.php
+++ b/tests/PhpWord/Writer/RTFTest.php
@@ -103,6 +103,7 @@ class RTFTest extends \PHPUnit_Framework_TestCase
      */
     public function testSavePhpOutput()
     {
+        $this->setOutputCallback(function() {});
         $phpWord = new PhpWord();
         $section = $phpWord->addSection();
         $section->addText(htmlspecialchars('Test', ENT_COMPAT, 'UTF-8'));
diff --git a/tests/PhpWord/Writer/Word2007Test.php b/tests/PhpWord/Writer/Word2007Test.php
index 76ba2114..656ac6df 100644
--- a/tests/PhpWord/Writer/Word2007Test.php
+++ b/tests/PhpWord/Writer/Word2007Test.php
@@ -166,6 +166,7 @@ class Word2007Test extends \PHPUnit_Framework_TestCase
      */
     public function testSetGetUseDiskCaching()
     {
+        $this->setOutputCallback(function() {});
         $phpWord = new PhpWord();
         $phpWord->addSection();
         $object = new Word2007($phpWord);