import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
-import com.google.common.base.Optional;
import com.google.common.collect.ImmutableMap;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.Map;
+import java.util.Optional;
import org.junit.Before;
import org.junit.Test;
import org.opendaylight.yangtools.util.UnmodifiableCollection;