Remove explanatory comments that restated what the code already says.
Kept only those that document non-obvious external contracts (the aiohttp
record-path patch's reason for re-feeding the body, and the warning
messages inside save_cassette that reach the user).
Previous attempt wrote to sys.__stderr__ from the test fixture. Under
xdist, fixtures run inside worker subprocesses whose stderr is captured
by the controller and only released to the live log on test failure —
so passing tests' verdicts were silently swallowed.
Round-trip via report.user_properties: the worker-side fixture stashes
the verdict on user_properties, xdist serializes it onto the report,
and a controller-side pytest_runtest_logreport hook writes it via the
TerminalReporter (the same plugin that emits PASSED/FAILED markers).
TerminalReporter is resolved lazily on first hook call because it's
not yet registered when conftest's pytest_configure runs.
Verified locally in both serial and xdist modes.
Previously, the per-test [VCR HIT/MISS/...] line was written via
TerminalReporter.write_line from inside fixture teardown. Pytest
captures that stream by default and only surfaces it on FAILED tests
(under 'Captured stdout teardown'), so passing tests' verdicts were
invisible in CI logs and the user couldn't tell whether the cache
was working.
Write directly to sys.__stderr__ so the line bypasses pytest's
capture entirely. Under xdist each worker has its own __stderr__
which CircleCI aggregates into the live job log alongside the
PASSED/FAILED markers.
A test that fails (incl. all the failing retries before a passing one)
can otherwise overwrite a known-good cassette with a 'bad luck'
recording. Tests like test_prompt_caching, which assert on provider
state across two calls, can produce a 200 response that semantically
fails the assertion — the 2xx filter doesn't catch this because the
HTTP layer is fine.
- pytest_runtest_makereport hook attaches each phase report to the
pytest item.
- _vcr_outcome_gate fixture (combining the verbose-mode reporter)
reads the call-phase outcome at teardown and informs the persister
via mark_test_outcome_for_cassette before vcrpy's Cassette.__exit__
triggers save_cassette.
- save_cassette consults the per-key 'did the test pass?' flag and
short-circuits when False, leaving any prior good recording intact.
- Defaults to passed=True when no marker is present so non-test
usage of the persister still works.
Set LITELLM_VCR_VERBOSE=1 to print a one-line cassette verdict per
test (HIT / MISS / PARTIAL / NOOP) showing replay vs new-recording
counts. Useful for local QA to confirm which tests actually exercised
the cache and which fell through to the live provider.
Stop falling back to REDIS_URL/REDIS_SSL_URL/REDIS_HOST for the VCR
persister. Sharing a Redis with the application cache risks cassettes
being wiped by tests that flush the app Redis.
vcrpy's aiohttp stub captures response bodies via 'await response.read()',
which drains aiohttp's StreamReader. Downstream consumers of the same
ClientResponse (litellm's AiohttpResponseStream, which iterates
response.content.iter_chunked) then see an empty body and surface as
JSON 'Expecting value: line 1 column 1 (char 0)' errors on every
record-path call.
The previous workaround set litellm.disable_aiohttp_transport=True for
the whole VCR-active session, which made the tests exercise pure httpx
instead of the production aiohttp transport. That hid the production
transport from coverage and surfaced its own bugs (e.g. the Azure
DELETE-with-empty-body case fixed in upstream staging).
Replace the workaround with a targeted monkey-patch that re-feeds the
captured body into the StreamReader via unread_data after vcrpy records
it. Tests now run through the same transport customers do, both on
first record and on replay, for both unary and streaming endpoints.
Verified locally against api.anthropic.com with the production
LiteLLMAiohttpTransport: record path passes (real network, 4.2s),
replay path passes (Redis cache, 1.8s).
litellm's default LiteLLMAiohttpTransport routes requests through aiohttp,
which sits below httpx and is invisible to vcrpy's httpx-stub interception.
Under vcrpy + aiohttp, requests reach the real network but responses come
back through the stubbed httpx transport as empty 200s, surfacing as
'Unable to get json response - Expecting value: line 1 column 1 (char 0)'
in providers like Anthropic, Gemini, and any other path that exercises the
aiohttp transport.
Disabling the aiohttp transport when the VCR persister is registered
forces all calls through pure httpx, which vcrpy can record and replay
correctly.
record_mode='once' refused to add new requests once any cassette
existed in Redis. Combined with filter_non_2xx_response (which drops
non-2xx responses from the saved cassette) and a 24h shared-Redis TTL,
a single transient API failure mid-test left the cassette stuck with
only the leading non-API requests (e.g. the model_prices fetch from
raw.githubusercontent.com), and every subsequent run for the next 24h
errored with 'Can't overwrite existing cassette'.
new_episodes records anything not already present, so partially
populated cassettes recover on the next run instead of poisoning the
suite for a full TTL window.
Removes commentary that restated the code, including:
- module-level banners explaining what the conftest does (covered by
Readme.md and the function bodies)
- docstrings on _scrub_response, _before_record_response, vcr_config,
_vcr_disabled, pytest_recording_configure (function names + bodies
are self-evident)
- inline notes about header filtering, match_on, etc.
- per-test docstrings restating the test name
Keeps the two non-obvious notes that aren't recoverable from the code:
the vcrpy/respx httpx-transport collision rationale on
_RESPX_CONFLICTING_FILES, the vcrpy "return None to skip persisting"
contract on filter_non_2xx_response, and the fixture-ordering
dependency on _vcr_record_retries.
Removes the YAML cassette feature entirely and replaces it with a
Redis-only flow. Every test in tests/llm_translation/ and
tests/llm_responses_api_testing/ is auto-marked @pytest.mark.vcr via
conftest.pytest_collection_modifyitems, so any provider call lands in
the Redis cache (litellm:vcr:cassette:<rel_path>, 24h TTL). First run
records, runs within the day replay, day rollover re-records and
surfaces upstream API drift within 24h.
VCR is on by default. Set LITELLM_VCR_DISABLE=1, or simply leave
REDIS_HOST unset, to opt out — both bypass the auto-marker entirely so
nothing about cassettes runs. record_mode is "once" so cache-miss
records and cache-hit replays.
The 8 existing respx-using files in tests/llm_translation are excluded
from the auto-marker (vcrpy and respx both patch the httpx transport;
applying both makes one silently win). The persister's own unit-test
file is also excluded so it doesn't recursively run inside a cassette.
The persister moved from tests/llm_translation/_vcr_redis_persister.py
to tests/_vcr_redis_persister.py so both conftests share it. The two
demo tests in test_anthropic_completion_vcr.py were ported into
test_anthropic_completion.py and the demo file was deleted.
Adds tests/_flush_vcr_cache.py + a Make target
(test-llm-translation-flush-vcr-cache) that scans
litellm:vcr:cassette:* and pipelines DELETEs, for the
"I want the next CI run to re-record now" workflow. Drops the now-dead
test-llm-translation-record target.
Provider keys are still required on cache-miss (which happens on first
run and once a day after that). Replay-mode runs need only Redis.
mateo-berri