@Test
public void testGetExtensionByIdWithServiceApi() {

    final ExtensionEntity extension = metadataService.getExtensionById("e3");
    assertNotNull(extension);
    assertEquals("e3", extension.getId());
    assertEquals("org.apache.nifi.ExampleService", extension.getName());
    assertEquals("{ \"name\" : \"org.apache.nifi.ExampleService\", \"type\" : \"CONTROLLER_SERVICE\" }", extension.getContent());
}