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, quota_management.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.

A skipped test asserts nothing, so its markers do not count. A cell is covered only when at least one test pytest would actually run declares it; a cell claimed by both a live test and a skipped one stays covered. Skip state comes from pytest's own evaluator, so skip and skipif resolve exactly as they do in the e2e run, which also means a skipif on an absent credential makes that cell uncovered in the environments where the test cannot run. Cells left uncovered this way are listed under the headline (and counted by litellm_e2e_coverage_skipped_markers) so an unskipped-pending gap is visible rather than inflating the number. The one skip the collector cannot see is pytest.skip() called from inside a test body, since it does not exist until the test runs.

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