diff --git a/composer.json b/composer.json
index 2ca7c71..22783b3 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
         "illuminate/events": "5.1.*|5.2.*|5.3.*|5.4.*|5.5.*"
     },
     "require-dev": {
-        "phpunit/phpunit": "~5.0",
+        "phpunit/phpunit": "~5.0|~6.0",
         "mockery/mockery": "~0.9.0",
         "orchestra/testbench": "~3.1"
     },
diff --git a/tests/CartAssertions.php b/tests/CartAssertions.php
index 6186860..c351f40 100644
--- a/tests/CartAssertions.php
+++ b/tests/CartAssertions.php
@@ -3,7 +3,7 @@
 namespace Gloudemans\Tests\Shoppingcart;
 
 use Gloudemans\Shoppingcart\Cart;
-use PHPUnit_Framework_Assert as PHPUnit;
+use PHPUnit\Framework\Assert as PHPUnit;
 
 trait CartAssertions
 {
diff --git a/tests/CartTest.php b/tests/CartTest.php
index 5745909..775e4a8 100644
--- a/tests/CartTest.php
+++ b/tests/CartTest.php
@@ -11,7 +11,6 @@ use Illuminate\Support\Collection;
 use Gloudemans\Shoppingcart\CartItem;
 use Illuminate\Support\Facades\Event;
 use Illuminate\Session\SessionManager;
-use Gloudemans\Shoppingcart\CartItemOptions;
 use Illuminate\Contracts\Auth\Authenticatable;
 use Gloudemans\Shoppingcart\ShoppingcartServiceProvider;
 use Gloudemans\Tests\Shoppingcart\Fixtures\ProductModel;