### Question:
DataTypeResolutionServiceImpl extends AbstractJargonService implements DataTypeResolutionService { @Override public String determineMimeTypeViaTika(final DataObject dataObject) throws JargonException { AutoDetectParser parser = new AutoDetectParser(); Detector detector = parser.getDetector(); Metadata md = new Metadata(); md.add(TikaMetadataKeys.RESOURCE_NAME_KEY, dataObject.getDataName()); MediaType mediaType; try { mediaType = detector.detect(null, md); } catch (IOException e) { throw new JargonException("io exception determining file type by extension", e); } return mediaType.toString(); } DataTypeResolutionServiceImpl();  DataTypeResolutionServiceImpl(final IRODSAccessObjectFactory irodsAccessObjectFactory,
			final IRODSAccount irodsAccount); @Override String resolveDataTypeWithProvidedAvuAndDataObject(final DataObject dataObject,
			final List<MetaDataAndDomainData> metadata); @Override String determineMimeTypeViaTika(final DataObject dataObject); static final String APPLICATION_IRODS_RULE; static final Logger log; }### Answer:
@Test public void testGetDataTypeFromExtension() throws Exception { IRODSAccount irodsAccount = TestingPropertiesHelper.buildBogusIrodsAccount(); IRODSAccessObjectFactory irodsAccessObjectFactory = Mockito.mock(IRODSAccessObjectFactory.class); DataTypeResolutionService resolutionService = new DataTypeResolutionServiceImpl(irodsAccessObjectFactory, irodsAccount); DataObject dataObject = new DataObject(); String dataName = "file.txt"; dataObject.setDataName(dataName); String actual = resolutionService.determineMimeTypeViaTika(dataObject); Assert.assertNotNull("null data type", actual); Assert.assertFalse("no data type", actual.isEmpty()); }