diff --git a/tests/Grant/AbstractGrantTest.php b/tests/Grant/AbstractGrantTest.php
index 542c78dc..11139bfb 100644
--- a/tests/Grant/AbstractGrantTest.php
+++ b/tests/Grant/AbstractGrantTest.php
@@ -459,6 +459,21 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
         $grantMock->validateScopes('basic   ');
     }
 
+    /**
+     * @expectedException     \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 11
+     */
+    public function testValidateScopesMissingScope()
+    {
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn(null);
+
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $grantMock->setScopeRepository($scopeRepositoryMock);
+
+        $grantMock->validateScopes('');
+    }
+
     public function testGenerateUniqueIdentifier()
     {
         $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);