StoreTest.php: added test for store zero

tests/phpunit/StoreTest.php

@@ -151,4 +151,11 @@ return;
         $this->assertEquals('female2', $this->store->getVar('gender', '', SANATIZE_ALLOW_ALNUMX), "Retrieve 'gender' from STORE_SIP");
     }
 
+    public function testGetVarStoreZero() {
+        //default prio  FSRD
+
+        $this->assertEquals(0, $this->store->getVar('fakename', '', STORE_ZERO), "Retrieve anything from STORE_ZERO");
+
+    }
+
 }