Transmit the complete --delete-during/--delete-delay per-directory plan set before the first data frame, so a mid-transfer abort has already applied every planned removal like rsync's generator; completed runs are unchanged. Route -d/--dirs through the same per-directory plans: the generator records only directories whose direct children it enumerated, so extras directly inside a listed directory are removed while an untraversed subdirectory's mirror is shielded (rsync's -d DIR/ --delete). Also shields a -x mount point's untraversed destination content.
Integration tests
The integration suite drives the built build/server and build/client
against local corpora. Unit tests live in tests/ (the custom C framework);
the Python suite here covers the full transfer pipeline, transports, features,
and rsync parity.
Running
# Full suite (excludes privilege-dependent tests on CI runners)
python3 -m pytest tests/integration/ -n 4 --dist=load -m "not setpriv"
# Fast PR subset only
python3 -m pytest tests/integration/ -n 4 --dist=load -m ci
The tests expect build/server and build/client (configure/build with CMake
first); common.py derives BUILD_DIR from the repository root.
Differential rsync-parity gate
test_differential_parity.py runs the same transfer with real
rsync 3.4.1 and with FastSync over separate destinations, then compares:
- the destination trees — relative paths, file content hashes, symlink targets, modes (where the case is about perms), and hard-link grouping;
- the normalized stdout for output-oriented flags (
-i,--out-format=...,--stats), after stripping volatile fields (timings, rates, wire byte counts) and directory-only itemize lines that FastSync's recursive scanner documents as absent.
FastSync mirrors the absolute source path under its receive root (see
get_dest_received_dir); the harness normalizes that layout (and the
-R/--files-from layouts) before comparing.
# Fast subset that guards the ✅ surface on pull requests
python3 -m pytest tests/integration/test_differential_parity.py -n 4 --dist=load -m parity_ci
# Full differential case table (`_CASES`): every row is marked `parity`, and a
# case with an allowlisted residual in `parity_caveats.py` is included too.
python3 -m pytest tests/integration/test_differential_parity.py -n 4 --dist=load -m parity
-m parity selects only the _CASES table in this module. Differential
coverage for options outside that table (--temp-dir, --delay-updates,
--dry-run, --fuzzy, the basis-dir options, -M over daemon/TCP, and
receiver filter-protect) lives in dedicated modules (test_option_parity.py,
test_parity_blockers.py, test_parity_quickwins.py, ...) and is not part of
this gate. The suite skips cleanly when rsync is not installed.
Allowlist (parity_caveats.py)
parity_caveats.py is the single data-driven allowlist of known differences.
Each entry maps a case id to the aspects that may differ (tree, stdout,
extra, rc) and cites the governing row in RSYNC_COMPAT.md:
CAVEATS = {
# no known residuals at present -- the burn-down reached zero
# "some_case_id": {"tree": "documented residual ... ref: RSYNC_COMPAT.md ..."},
}
A differential mismatch in an aspect that is not listed fails the gate with a readable tree/stdout diff.
If a case is allowlisted but now matches rsync, the gate emits a loud warning
naming the stale entry — that is the parity burn-down signal. Run with
FASTSYNC_PARITY_STRICT=1 to make stale entries fail instead (the full CI
parity job sets this). To add a residual:
- Reproduce it with
-m parityand read the failure's tree/stdout diff. - Confirm it is a documented
⚠️/❌residual (or get the✅row reclassified) and cite the row. - Add the case id and aspect(s) to
CAVEATS, keeping the reason concise.
Do not allowlist an undocumented divergence from a ✅ row — fix it or get the
row reclassified first.