### Question:
PatternQueryHandler extends InstancesQueryHandler { @Override protected List<String> getInstances(String queryStr) { List<String> instances = new ArrayList<>(); try{ QueryFactory.create(queryStr); LOGGER.debug("[QueryHandler: {{}}] Query is already an instance: {{}}", this.getClass().getName(), queryStr); instances.add(queryStr); return instances; }catch(Exception e) { } Set<String> varNames = new HashSet<String>(); String command = replaceVars(queryStr, varNames); ParameterizedSparqlString pss = new ParameterizedSparqlString(); pss.setCommandText(command); ResultSet exchange = getInstanceVars(pss, varNames); if(!exchange.hasNext()) { LOGGER.warn("[QueryHandler: {{}}] Query has no solution, will use variables instead of var instances: {{}}", this.getClass().getName(), queryStr); instances.add(command); } while(exchange.hasNext()) { QuerySolution solution = exchange.next(); for(String var : exchange.getResultVars()) { pss.clearParam(var); pss.setParam(var, solution.get(var)); } instances.add(pss.toString()); } LOGGER.debug("Found instances {}", instances); return instances; } PatternQueryHandler(List<Worker> workers, String endpoint);  PatternQueryHandler(LinkedList<Worker> workers, String endpoint, String limit);  PatternQueryHandler(LinkedList<Worker> workers, String endpoint, Long limit);   }### Answer:
@Test public void testPatternExchange(){ List<String> instances = getHandler().getInstances(queryStr); assertEquals(expectedInstances, instances); }