### Question:
CompressionStrategy implements BlobStrategy { @Override public byte[] reverse(byte[] blob) throws TokenStrategyFailedException { Reject.ifNull(blob); final int lengthGuess = blob.length * 2; final ByteArrayOutputStream bout = new ByteArrayOutputStream(lengthGuess); try { GZIPInputStream inputStream = new GZIPInputStream(new ByteArrayInputStream(blob)); IOUtils.copy(inputStream, bout); inputStream.close(); } catch (IOException e) { throw new TokenStrategyFailedException(e); } return bout.toByteArray(); }  @Override byte[] perform(byte[] blob); @Override byte[] reverse(byte[] blob);  }### Answer:
@Test (expectedExceptions = NullPointerException.class) public void shouldRejectIfNullBlobOnReverse() throws TokenStrategyFailedException { compression.reverse(null); }