code: package it.unibz.inf.ontop.rdf4j.repository;
  
  import com.google.common.collect.ImmutableSet;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  
  import java.io.IOException;
  import java.sql.SQLException;
  
  import static org.junit.Assert.assertEquals;
  
  public class RDF4JR2RMLConstantLangTagTest extends AbstractRDF4JTest {
  
      @BeforeClass
      public static void before() throws IOException, SQLException {
          initR2RML("/prof/prof.sql", "/prof/prof-cst-langtag.mapping.ttl");
      }
  
      @AfterClass
      public static void after() throws SQLException {
          release();
      }
  
      @Test
      public void testLangTag1() {
          String query = "PREFIX : <http://example.org/voc#>\n" +
                  "SELECT *\n" +
                  "WHERE {\n" +
                  "  ?p a :Professor ; :label ?v \n" +
                  "  FILTER (lang(?v)='it')\n" +
                  "}";
          runQueryAndCompare(query, ImmutableSet.of("Professore"));
      }
  }
  