diff --git a/composer.json b/composer.json
index 874ee51..7bc3835 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,8 @@
     "illuminate/console": "^5.2"
   },
   "require-dev": {
-    "mockery/mockery": "dev-master@dev"
+    "mockery/mockery": "dev-master@dev",
+    "phpunit/phpunit": "6.*"
   },
   "autoload": {
     "psr-4": {
diff --git a/tests/RepositoryTest.php b/tests/RepositoryTest.php
index 7718f6b..73eb112 100644
--- a/tests/RepositoryTest.php
+++ b/tests/RepositoryTest.php
@@ -3,7 +3,7 @@
 namespace Bosnadev\Tests\Repositories;
 
 use \Mockery as m;
-use \PHPUnit_Framework_TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 
 class RepositoryTest extends TestCase {