### Question:
B2ContentSourceWithByteProgressListener implements B2ContentSource { @Override public long getContentLength() throws IOException { return source.getContentLength(); } B2ContentSourceWithByteProgressListener(B2ContentSource source,
                                            B2ByteProgressListener listener); @Override long getContentLength(); @Override String getSha1OrNull(); @Override Long getSrcLastModifiedMillisOrNull(); @Override InputStream createInputStream(); @Override String toString();  }### Answer:
@Test public void testGetContentLength() throws Exception { when(wrappedSource.getContentLength()).thenReturn(6L); assertEquals(6L, source.getContentLength()); }