added missing test

tests/Solarium/Client/Request/SelectTest.php

@@ -113,4 +113,21 @@ class Solarium_Client_Request_SelectTest extends PHPUnit_Framework_TestCase
             urldecode($request->getUrl())
         );
     }
+
+    public function testUnknownFacetType()
+    {
+        $this->_query->addFacet(new UnknownFacet(array('key' => 'f1', 'field' => 'owner')));
+        $this->setExpectedException('Solarium_Exception');
+        new Solarium_Client_Request_Select($this->_options, $this->_query);
+    }
 }
+
+class UnknownFacet extends Solarium_Query_Select_Facet_Field{
+
+    public function getType()
+    {
+        return 'unknown';
+    }
+
+
+}
\ No newline at end of file