### Question:
Base64Wrapper { public String encodeB64Bytes(byte[] bytes) { return Base64.encodeBase64String(bytes); }  String encodeB64Bytes(byte[] bytes); byte[] decodeB64Bytes(String encodedBytes);  }### Answer:
@Test public void testBase64Encoder() { String result = wrapper.encodeB64Bytes(rawData); assertEquals(result, encodedData); }
@Test public void testBase64EncoderNullData() { String result = wrapper.encodeB64Bytes(null); assertEquals(result, null); }