diff --git a/.travis.yml b/.travis.yml
index 78e2cab..451832b 100755
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,8 +7,13 @@ php:
   - 5.6
   - 7.0
   - 7.1
+  - nightly
   - hhvm
 
+matrix:
+    allow_failures:
+        - php: hhvm
+
 before_script:
   - composer install --no-interaction
 
diff --git a/composer.json b/composer.json
index 87a6119..e9769a3 100755
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
         "php": ">=5.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "4.*",
+        "phpunit/phpunit": "^4.8.35|^5.7|^6.0",
         "squizlabs/php_codesniffer": "1.*"
     }
 }
diff --git a/tests/EnumTest.php b/tests/EnumTest.php
index 72ec873..c468017 100755
--- a/tests/EnumTest.php
+++ b/tests/EnumTest.php
@@ -11,7 +11,7 @@
  * @author Daniel Costa <danielcosta@gmail.com>
  * @author Mirosław Filip <mirfilip@gmail.com>
  */
-class EnumTest extends \PHPUnit_Framework_TestCase
+class EnumTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * getValue()
@@ -40,14 +40,11 @@ public function testGetKey()
 
     /**
      * @dataProvider invalidValueProvider
+     * @expectedException UnexpectedValueException
+     * @expectedExceptionMessage is not part of the enum MyCLabs\Tests\Enum\EnumFixture
      */
     public function testCreatingEnumWithInvalidValue($value)
     {
-        $this->setExpectedException(
-            '\UnexpectedValueException',
-            'Value \'' . $value . '\' is not part of the enum MyCLabs\Tests\Enum\EnumFixture'
-        );
-
         new EnumFixture($value);
     }