### Question:
VFSRegistryHelper { public Object readEntry(final Path path) throws Exception { final String entryContent = ioService.readAllString(path); final VFSRegistryEntry entry = entryMarshaller.unmarshal(entryContent); final Marshaller marshaller = marshallerRegistry.get(Class.forName(entry.getContentType())); if (marshaller == null) { throw new Exception("No marshaller was found for class: " + entry.getContentType()); } return marshaller.unmarshal(entry.getContent()); } VFSRegistryHelper(); @Inject  VFSRegistryHelper(final VFSMarshallerRegistry marshallerRegistry,
                             final @Named("ioStrategy") IOService ioService,
                             final @Named("systemFS") FileSystem fileSystem); Path ensureDirectory(final String directory); String md5Hex(String content); void storeEntry(final Path path,
                           final Object value); Object readEntry(final Path path); List<Object> readEntries(final Path rootPath,
                                    final DirectoryStream.Filter<Path> filter); void writeBatch(final Path path,
                           final String content); void deleteBatch(final Path path);  }### Answer:
@Test public void testReadEntryWhenMarshallerNotExists() throws Exception { when(ioService.readAllString(path)).thenReturn(MARSHALLED_ENTRY); when(entryMarshaller.unmarshal(MARSHALLED_ENTRY)).thenReturn(entry); when(entry.getContentType()).thenReturn(Object.class.getName()); when(marshallerRegistry.get(Object.class.getClass())).thenReturn(null); expectedException.expectMessage("No marshaller was found for class: " + entry.getContentType()); registryHelper.readEntry(path); }
@Test public void testReadEntry() throws Exception { when(ioService.readAllString(path)).thenReturn(MARSHALLED_ENTRY); when(entryMarshaller.unmarshal(MARSHALLED_ENTRY)).thenReturn(entry); when(entry.getContentType()).thenReturn(Object.class.getName()); when(entry.getContent()).thenReturn(MARSHALLED_VALUE); when(marshallerRegistry.get(any(Class.class))).thenReturn(marshaller); Object unmarshalledValue = mock(Object.class); when(marshaller.unmarshal(MARSHALLED_VALUE)).thenReturn(unmarshalledValue); Object result = registryHelper.readEntry(path); assertEquals(unmarshalledValue, result); }