Unit tests for individual LLM providers.
Name of the test file is the name of the LLM provider - e.g. test_openai.py is for OpenAI.
Redis-backed VCR cache
Every test in this directory is auto-decorated with @pytest.mark.vcr (via
conftest.py). The first time a test runs we hit the live provider and
record the HTTP exchange into Redis under
litellm:vcr:cassette:<test_id>. Every subsequent run within 24h replays
from Redis without touching the network. The 24h TTL means each new day's
first run records again, so upstream API drift surfaces within a day.
The persister, header scrubbing, and 2xx-only filtering are defined in
tests/_vcr_redis_persister.py. Files that already use respx (which
patches the same httpx transport vcrpy does) are excluded from the
auto-marker — see _RESPX_CONFLICTING_FILES in conftest.py.
The same VCR cache is used by other test directories that exercise live
provider APIs. The reusable conftest plumbing lives in
tests/_vcr_conftest_common.py and is wired into:
tests/llm_translation/tests/llm_responses_api_testing/tests/audio_tests/tests/batches_tests/tests/guardrails_tests/tests/image_gen_tests/tests/litellm_utils_tests/tests/local_testing/(coverslocal_testing_part1,local_testing_part2,litellm_router_testing,litellm_assistants_api_testing,langfuse_logging_unit_tests)tests/logging_callback_tests/tests/pass_through_unit_tests/tests/router_unit_tests/tests/unified_google_tests/
Test directories that run LiteLLM proxy in Docker (e.g. build_and_test,
proxy_logging_guardrails_model_info_tests, proxy_store_model_in_db_tests)
are intentionally not included: VCR.py patches the in-process httpx
transport, so it cannot intercept the LLM calls that originate inside the
Docker container.
Required environment
CASSETTE_REDIS_URL — separate Redis instance from the application
Redis (REDIS_URL/REDIS_HOST) so test cassettes are not flushed by
proxy tests. Provider credentials (ANTHROPIC_API_KEY, OPENAI_API_KEY,
AWS_*, etc.) are needed only on cache-miss (the daily re-record), not
on replay.
Flushing the cache
When you want the next run to re-record immediately instead of waiting for the 24h TTL:
make test-llm-translation-flush-vcr-cache
Disabling VCR
Skip the cache entirely (every call goes live, no recording):
LITELLM_VCR_DISABLE=1 uv run pytest tests/llm_translation/test_<file>.py