code: package it.unibz.inf.ontop.owlapi;
  
  import com.google.common.collect.ImmutableList;
  import org.junit.*;
  
  import static org.junit.Assert.assertFalse;
  
  
  public class NullIfTest extends AbstractOWLAPITest {
  
      @BeforeClass
      public static void before() throws Exception {
          initOBDA("/nullif/nullif-create.sql",
                  "/nullif/nullif.obda",
                  "/nullif/nullif.ttl");
      }
  
      @AfterClass
      public static void after() throws Exception {
          release();
      }
  
      @Test
      public void testSelectNumbers() throws Exception {
          String query = "PREFIX ex: <http://example.org/>" +
                  "SELECT ?v\n" +
                  "WHERE { ?s ex:hasNumber ?v }";
  
          String sql = checkReturnedValuesAndReturnSql(query, "v", ImmutableList.of("\"2\"^^xsd:integer"));
          assertFalse(sql.toUpperCase().contains("NULLIF"));
      }
  }
  