### Question:
DefaultNamespaceCreator extends BaseStepExecutor<EmptyArguments> { @Override public void execute(EmptyArguments arguments) throws FileAlreadyExistsException { try { if (!namespaceAdmin.exists(NamespaceId.DEFAULT)) { namespaceAdmin.create(NamespaceMeta.DEFAULT); LOG.info("Successfully created namespace '{}'.", NamespaceMeta.DEFAULT); } } catch (FileAlreadyExistsException e) { throw e; } catch (NamespaceAlreadyExistsException e) { } catch (Exception e) { throw new RetryableException(e); } } @Inject  DefaultNamespaceCreator(NamespaceAdmin namespaceAdmin); @Override void execute(EmptyArguments arguments);  }### Answer:
@Test public void test() throws Exception { try { namespaceAdmin.get(NamespaceId.DEFAULT); Assert.fail("Default namespace should not exist."); } catch (NamespaceNotFoundException e) { } BootstrapStepResult result = defaultNamespaceCreator.execute("label", new JsonObject()); BootstrapStepResult expected = new BootstrapStepResult("label", BootstrapStepResult.Status.SUCCEEDED); Assert.assertEquals(expected, result); Assert.assertEquals(NamespaceMeta.DEFAULT, namespaceAdmin.get(NamespaceId.DEFAULT)); result = defaultNamespaceCreator.execute("label", new JsonObject()); expected = new BootstrapStepResult("label", BootstrapStepResult.Status.SUCCEEDED); Assert.assertEquals(expected, result); Assert.assertEquals(NamespaceMeta.DEFAULT, namespaceAdmin.get(NamespaceId.DEFAULT)); }