code: package it.unibz.inf.ontop.docker.mysql;
  
  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;
  
  /**
   * TODO: describe
   */
  public class LeftJoinPullOutEqualityTest extends AbstractVirtualModeTest {
  
      private static final String owlFileName = "/mysql/pullOutEq/pullOutEq.ttl";
      private static final String obdaFileName = "/mysql/pullOutEq/pullOutEq.obda";
      private static final String propertyFileName = "/mysql/pullOutEq/pullOutEq.properties";
  
      private static OntopOWLEngine REASONER;
      private static OntopOWLConnection CONNECTION;
  
      @BeforeClass
      public static void before() throws OWLOntologyCreationException {
          REASONER = createReasoner(owlFileName, obdaFileName, propertyFileName);
          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 testFlatLeftJoins() throws  OWLException {
          countResults(1, "PREFIX : <http://example.com/vocab#>" +
                  "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>" +
                  "SELECT ?p ?firstName ?lastName " +
                  "WHERE { " +
                  "    ?p :age \"33\"^^xsd:int . " +
                  "    OPTIONAL { ?p :firstName ?firstName }" +
                  "    OPTIONAL { ?p :lastName ?lastName }" +
                  "}");
      }
  
      @Test
      public void testNestedLeftJoins() throws  OWLException {
          countResults(1, "PREFIX : <http://example.com/vocab#>" +
                  "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>" +
                  "SELECT ?p ?firstName ?lastName " +
                  "WHERE { " +
                  "    ?p :age \"33\"^^xsd:int . " +
                  "    OPTIONAL { ?p :firstName ?firstName " +
                  "               OPTIONAL { ?p :lastName ?lastName }" +
                  "    }" +
                  "}");
      }
  
      @Test
      public void testJoinAndFlatLeftJoins() throws  OWLException {
          countResults(1, "PREFIX : <http://example.com/vocab#>" +
                  "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>" +
                  "SELECT ?p ?firstName ?lastName " +
                  "WHERE { " +
                  "    ?p :gender ?g . " +
                  "    ?p :age \"33\"^^xsd:int . " +
                  "    FILTER (str(?g) = \"F\") " +
                  "    OPTIONAL { ?p :firstName ?firstName }" +
                  "    OPTIONAL { ?p :lastName ?lastName }" +
                  "}");
      }
  
      @Test
      public void testBasic() throws OWLException {
          countResults(1, "PREFIX : <http://example.com/vocab#>" +
                  "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>" +
                  "SELECT ?p " +
                  "WHERE { " +
                  "    ?p :age \"33\"^^xsd:int . " +
                  "}");
      }
  }
  