code: package it.unibz.inf.ontop.owlapi;
  
  import com.google.common.collect.ImmutableList;
  import org.junit.*;
  
  public class ConditionalAsLeftJoinTest extends AbstractOWLAPITest {
  
      @BeforeClass
      public static void setUp() throws Exception {
          initOBDA("/test/conditional_leftjoin/conditional_leftjoin_create.sql",
                  "/test/conditional_leftjoin/conditional_leftjoin_test.obda",
                  "/test/conditional_leftjoin/conditional_leftjoin_test.owl");
      }
  
      @AfterClass
      public static void tearDown() throws Exception {
          release();
      }
  
      @Test
      public void testQuery() throws Exception {
  
          String query = "PREFIX : <http://www.semanticweb.org/ontologies/2016/10/untitled-ontology-2#>\n" +
                  "SELECT ?v \n" +
                  "WHERE {\n" +
                  " :Tartaruga a :VegetarianRestaurant .\n" +
                  "OPTIONAL { :Tartaruga :hasAddress ?v }\n" +
                  "}";
  
          checkReturnedValues(query, "v", ImmutableList.of(
                  "<http://www.semanticweb.org/ontologies/2016/10/untitled-ontology-2#aa>"));
      }
  
  }
  