verify(mockChunk2, times(1)).encode(eq(buffer), eq(HEADER_SIZE + CHUNK_SIZE));
        }

        @Test
        @DisplayName("Should accumulate encoded bytes from chunks")
        void testAccumulatesEncodedBytes() {
            // Given
            byte[] sourceKey = new byte[SOURCE_KEY_SIZE];
            SrvCopychunk mockChunk1 = mock(SrvCopychunk.class);
            SrvCopychunk mockChunk2 = mock(SrvCopychunk.class);