### Question:
B2UploadingPartStorer implements B2PartStorer { @Override public B2Part storePart( B2LargeFileStorer largeFileCreationManager, B2UploadListener uploadListener) throws IOException, B2Exception { return largeFileCreationManager.uploadPart(partNumber, contentSource, uploadListener); } B2UploadingPartStorer(int partNumber, B2ContentSource contentSource); @Override int getPartNumber(); @Override long getPartSizeOrThrow(); @Override B2Part storePart(
            B2LargeFileStorer largeFileCreationManager,
            B2UploadListener uploadListener); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void testStorePart() throws IOException, B2Exception { final B2ContentSource contentSource = mock(B2ContentSource.class); final B2UploadingPartStorer partStorer = new B2UploadingPartStorer(PART_NUMBER, contentSource); final B2LargeFileStorer largeFileStorer = mock(B2LargeFileStorer.class); when(largeFileStorer.uploadPart(anyInt(), anyObject(), anyObject())).thenReturn(part); assertEquals(part, partStorer.storePart(largeFileStorer, uploadListener)); verify(largeFileStorer).uploadPart(2, contentSource, uploadListener); }