code: package it.unibz.inf.ontop.docker.postgres;
  
  import it.unibz.inf.ontop.docker.AbstractVirtualModeTest;
  import it.unibz.inf.ontop.owlapi.OntopOWLEngine;
  import it.unibz.inf.ontop.owlapi.connection.OntopOWLConnection;
  import it.unibz.inf.ontop.owlapi.connection.OntopOWLStatement;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.semanticweb.owlapi.model.OWLException;
  import org.semanticweb.owlapi.model.OWLOntologyCreationException;
  
  import static org.junit.Assert.assertEquals;
  
  
  /**
   * Test class to solve the bug that generates unbound variables in the mapping.
   * Use the postgres IMDB database and a simple obda file with the problematic mapping.
   *
   * Solved modifying the method enforce equalities in DatalogNormalizer
   * to consider the case of nested equivalences in mapping
   */
  public class UnboundVariableIMDbTest extends AbstractVirtualModeTest {
  
  	static final String owlfile = "/pgsql/imdb/ontologyIMDB.owl";
  	static final String obdafile = "/pgsql/imdb/ontologyIMDBSimplify.obda";
  	static final String propertyfile = "/pgsql/imdb/movieontology.properties";
  
  	private static OntopOWLEngine REASONER;
  	private static OntopOWLConnection CONNECTION;
  
  	@BeforeClass
  	public static void before() throws OWLOntologyCreationException {
  		REASONER = createReasoner(owlfile, obdafile, propertyfile);
  		CONNECTION = REASONER.getConnection();
  	}
  
  	@Override
  	protected OntopOWLStatement createStatement() throws OWLException {
  		return CONNECTION.createStatement();
  	}
  
  	@AfterClass
  	public static void after() throws Exception {
  		CONNECTION.close();
  		REASONER.close();
  	}
  
  	@Test
  	public void testIMDBSeries() throws Exception {
  		String query = "PREFIX : <http://www.seriology.org/seriology#>\n" +
  				"SELECT DISTINCT ?p WHERE { ?p a :Series . } LIMIT 10";
  		countResults(10, query);
  	}
  
  	@Test
  	public void testSubStr2WrongArgument() throws OWLException {
  		countResults(2, "SELECT * WHERE {\n" +
  				"  {\n" +
  				"    SELECT DISTINCT ?b {\n" +
  				"      {\n" +
  				"        SELECT * {\n" +
  				"          VALUES ?b { 2 }\n" +
  				"        }\n" +
  				"      }\n" +
  				"      UNION {\n" +
  				"        SELECT * {\n" +
  				"          VALUES ?b { \"aa\" \"aa\" }\n" +
  				"        }\n" +
  				"      }\n" +
  				"    }\n" +
  				"  }\n" +
  				"  BIND (SUBSTR(\"yyy\", ?b) AS ?v)\n" +
  				"}");
  	}
  
  	@Test
  	public void testSubStr3WrongArgument() throws OWLException {
  		countResults(2, "SELECT * WHERE {\n" +
  				"  {\n" +
  				"    SELECT DISTINCT ?b {\n" +
  				"      {\n" +
  				"        SELECT * {\n" +
  				"          VALUES ?b { 2 }\n" +
  				"        }\n" +
  				"      }\n" +
  				"      UNION {\n" +
  				"        SELECT * {\n" +
  				"          VALUES ?b { \"aa\" \"aa\" }\n" +
  				"        }\n" +
  				"      }\n" +
  				"    }\n" +
  				"  }\n" +
  				"  BIND (SUBSTR(\"yyy\", ?b, ?b) AS ?v)\n" +
  				"}");
  	}
  }
  