### Question:
FileAgent implements IFileAgent { @Override public byte[] readCache(String key) { if (cache == null) { return null; } if (key == null) { return null; } Path cacheFile = cache.resolve(key); if (!Files.exists(cacheFile)) { return null; } try { return Files.readAllBytes(cacheFile); } catch (IOException e) { } return null; } FileAgent(final Path root, final Path cache); @Override File getRoot(); @Override void writeCache(String key, byte[] data); @Override byte[] readCache(String key);  }### Answer:
@Test public void testRead() { byte[] read = fileAgent.readCache("testRead"); assertNull(read); }