litellm/tests/e2e/coverage_registry

e2e coverage registry

This directory is the denominator for e2e test coverage: the set of behaviors we want covered, one row per behavior, checked into the repo so coverage is a number we can track instead of a guess. It implements the plan in the "E2E Coverage Tracking" note; the naming grammar lives in tests/e2e/CLAUDE.md.

The model

A cell is one customer-noticeable behavior a single e2e test can assert pass/fail on, for example llm.chat_completions.bedrock_converse.tool_use.stream.works. Cells are grouped module > feature > test, with LLM cells split into Core LLMs and Non-Core LLMs for dashboarding. Each cell carries a tier (P0/P1/P2), a source, and a fail_before_fix flag.

The rows live in per-prefix YAML files (llm_*.yaml, mgmt.yaml, mcp.yaml, reliability.yaml, logging.yaml, guardrail.yaml, other.yaml) and validate against the discriminated union in schema.py, so an LLM row cannot carry a guardrail field and vice versa. llm rows with subject_endpoint of chat_completions, messages, or responses roll up to Core LLMs; all other LLM endpoints roll up to Non-Core LLMs. LLM endpoint, route, and capability values are typed in schema.py, so new taxonomy values require an explicit schema change. logging and guardrail are two id-prefixes that roll up into the single Logging & Guardrails dashboard module.

A test declares what it covers with a marker:

@pytest.mark.covers("llm.chat_completions.openai.tool_use.stream.works")
def test_openai_streaming_tool_calls(self) -> None:
    ...

The number

collector.py diffs the registry against those markers and reports coverage per module. It is static: a collect-only pass reads the markers, so it runs no test and needs no live proxy. Whether a covered cell currently passes or fails is a separate, live concern.

cd tests/e2e && PYTHONPATH=. python -m coverage_registry.collector

Use --format loki after the e2e pytest run in the same Kubernetes job/pod to print structured stdout lines for Loki:

cd tests/e2e && PYTHONPATH=. python -m coverage_registry.collector --format loki --strict

This emits exactly one COVERAGE_TOTAL line and one COVERAGE_MODULE line per module in MODULE_ORDER, in that order. Loki uses log-safe module= labels from LOKI_MODULE_LABELS (core_llms, management_ui, etc.) so existing JSON and Prometheus consumers keep their human-readable module names unchanged.

The headline is overall coverage. The collector also lists markers that point at ids not in the registry, so a typo or an unenumerated behavior surfaces instead of being silently dropped.

Use strict mode in CI once existing draft markers are reconciled:

cd tests/e2e && PYTHONPATH=. python -m coverage_registry.collector --strict

Strict mode exits non-zero on @pytest.mark.covers(...) ids that are not checked into the registry. Add --fail-on-collection-errors when the job should also fail on pytest collection errors.

Status: this is a draft for review

The cells were enumerated from the codebase and the tiers are a first proposal. Known things to settle before treating the set as final:

• tiers are proposed, not signed off; 125 P0 is a lot to prove fail-before-fix, so P0 may want tightening
• a few cells need a support check or a prune (for example llm.embeddings.anthropic.* and reliability.perf.throughput.under_slo)
• auth is covered in two places (other.auth.* and the mgmt authz assertions); the boundary needs a decision, and the auth cluster may deserve promotion to its own module
• the P2 "niche" cells each stand in for a large tail of integrations/providers by design, so the denominator is deliberately P0-weighted rather than a full inventory