public void testStartAndEndTypes() {
final Map<String, String> meta1 = new HashMap<>();
final Map<String, String> meta2 = new HashMap<>();
meta1.put("a", "1");
meta2.put("b", "2");
runNetworkDefinition(new NetworkDefiner() {
{
component("generator", IntegerGenerator.class);
component("metaadder", AddMetadata.class);
component("extractor", MetadataExtractor.class);
component("collector", ToCollection.class);