### Question:
DiskBasedCache implements Cache { @Override public synchronized Entry get(String key) { CacheHeader entry = mEntries.get(key); if (entry == null) { return null; } File file = getFileForKey(key); try { CountingInputStream cis = new CountingInputStream( new BufferedInputStream(createInputStream(file)), file.length()); try { CacheHeader entryOnDisk = CacheHeader.readHeader(cis); if (!TextUtils.equals(key, entryOnDisk.key)) { VolleyLog.d("%s: key=%s, found=%s", file.getAbsolutePath(), key, entryOnDisk.key); removeEntry(key); return null; } byte[] data = streamToBytes(cis, cis.bytesRemaining()); return entry.toCacheEntry(data); } finally { cis.close(); } } catch (IOException e) { VolleyLog.d("%s: %s", file.getAbsolutePath(), e.toString()); remove(key); return null; } } DiskBasedCache(File rootDirectory, int maxCacheSizeInBytes);  DiskBasedCache(File rootDirectory); @Override synchronized void clear(); @Override synchronized Entry get(String key); @Override synchronized void initialize(); @Override synchronized void invalidate(String key, boolean fullExpire); @Override synchronized void put(String key, Entry entry); @Override synchronized void remove(String key); File getFileForKey(String key);  }### Answer:
@Test public void testEmptyInitialize() { assertThat(cache.get("key"), is(nullValue())); }