### Question:
DbImpl implements DB { @Override public byte[] get(byte[] key) throws DBException { return get(key, new ReadOptions()); } DbImpl(File databaseDir, Options options); @Override void close(); @Override String getProperty(String name); void flushMemTable(); void compactRange(int level, Slice start, Slice end); void checkBackgroundException(); @Override byte[] get(byte[] key); @Override byte[] get(byte[] key, ReadOptions options); @Override void put(byte[] key, byte[] value); @Override Snapshot put(byte[] key, byte[] value, WriteOptions options); @Override void delete(byte[] key); @Override Snapshot delete(byte[] key, WriteOptions options); @Override void write(WriteBatch updates); @Override Snapshot write(WriteBatch updates, WriteOptions options); Snapshot writeInternal(WriteBatchImpl updates, WriteOptions options); @Override WriteBatch createWriteBatch(); @Override SeekingIteratorAdapter iterator(); @Override SeekingIteratorAdapter iterator(ReadOptions options); @Override Snapshot getSnapshot(); void compactMemTable(); @Override long[] getApproximateSizes(Range... ranges); long getApproximateSizes(Range range); long getMaxNextLevelOverlappingBytes(); @Override void suspendCompactions(); @Override void resumeCompactions(); @Override void compactRange(byte[] begin, byte[] end); static final String TAG; }### Answer:
@Test public void testEmpty() throws Exception { Options options = new Options(); File databaseDir = this.databaseDir; DbStringWrapper db = new DbStringWrapper(options, databaseDir); assertNull(db.get("foo")); }