* createSource(DataModelDefinition, ExporterDescription, TestContext)}.
* @throws Exception if failed
*/
@Test
public void open() throws Exception {
Desc desc = MockExporterRetriever.create("Hello, world!");
ClassLoader cl = register(ExporterRetriever.class, MockExporterRetriever.class);
SpiExporterRetriever target = new SpiExporterRetriever(cl);
DataModelSource source = target.createSource(ValueDefinition.of(String.class), desc, EMPTY);
assertThat(ValueDefinition.of(String.class).toObject(source.next()), is("Hello, world!"));