### Question:
AbstractFileCache { public synchronized void clear() { int clearedFiles = 0; for (File file : this.getAllFiles()) { if (file.delete()) { clearedFiles++; } else { LOGGER.warn(String.format(Messages.getString("AbstractFileCache.Warn.CouldNotDeleteClearing"), file.getAbsolutePath())); } } if (clearedFiles > 0) { LOGGER.info(String.format(Messages.getString("AbstractFileCache.Info.Cleared"), clearedFiles)); } } protected  AbstractFileCache(File cacheDirectory, String prefix, String suffix, final int maxAgeInSeconds); synchronized void clear(); synchronized boolean containsKey(K key); synchronized byte[] get(K key); synchronized InputStream getAsInputStream(K key); File getCacheDirectory(); File getCacheFile(K key); synchronized void purge(); synchronized void put(K key, byte[] value); synchronized void putFile(K key, File file, boolean move); synchronized void remove(K key);  }### Answer:
@Test public void testClear() throws CacheException { byte[] testBytes = "test".getBytes(StandardCharsets.US_ASCII); underTest.put("test", testBytes); underTest.clear(); byte[] resultBytes = underTest.get("test"); assertNull(resultBytes); }