Covers, for both downloadFile and downloadThumbnail:
- a multi-chunk body whose TAG_FINAL chunk never arrived is rejected
with a truncation error;
- an empty body is rejected as truncation rather than written as a
zero-byte file;
- after a truncation or chunk-authentication failure the destination
path does not exist and no temporary scratch file is left behind;
- an existing file at the destination survives a failed download
byte for byte, and is replaced atomically by a successful one;
- the existing success cases still produce identical bytes and an
identical DownloadResult.
Adds an encryptMultiChunkBody helper that frames leading chunks at
exactly STREAM_CHUNK_SIZE so the downloader's fixed-size re-splitting
lines up, plus a multi-chunk success case as the positive control.
Also pins the new STREAM_TAG_FINAL crypto export against libsodium's
own constant, since it must be declared as a literal: libsodium
attaches its constants only after sodium.ready resolves, well after
this library's modules are evaluated.
These fail until the implementation lands, per the repo's TDD workflow.
German for 'quack', matching the Ente (German for 'duck') naming. All
references updated: package name, CLI binary, X-Client-Package header,
test descriptions, temp dir prefixes, README, Makefile docker tag.
downloadFile streams the encrypted body from the CDN, buffers it to
the 4 MiB + 17 encrypted chunk boundary, decrypts each chunk via
secretstream pull, and writes the concatenated plaintext to disk.
downloadThumbnail does the same for the thumbnail CDN.
4 unit tests (single-chunk, large single-chunk, filename fallback,
thumbnail) + live integration test that downloads a real 472 KB JPEG
from the dev account and verifies it lands on disk.
Uses mkdtempSync for temp directories (not manual timestamp paths).
4 tests: single-chunk download, metadata-title fallback filename,
multi-chunk stream (50-byte chunks to exercise the buffering/split
logic without allocating 4 MiB), and thumbnail download.
Tests encrypt payloads with sodium's secretstream push, serve them
from a mock fetch, and verify the decrypted file on disk.
