### Question:
RetrofitOutputResource implements OutputResource { @Override public long getLength() { try { return mResponse.contentLength(); } catch (IOException e) { return -1; } } RetrofitOutputResource(ResponseBody input); @Override String getMimeType(); @Override long getLength(); @Override InputStream getStream();  }### Answer:
@Test public void shouldDelegateLength() throws IOException { objectUnderTest.getLength(); verify(mTypedInput, times(1)).contentLength(); }