# ECP-0047: Coverage Reporting (cargo-llvm-cov)

## Why

We want high confidence in stream processing, transport, and cryptographic verification code.
That requires:
- repeatable coverage measurement, and
- a visible baseline so we can drive coverage up without guessing.

## Proposal

Adopt `cargo llvm-cov` as the canonical Rust coverage tool in this repo (already provided by `flake.nix`).

Add:
- `scripts/coverage.sh` to generate an HTML report and write a summary table to `tmp/coverage/summary.txt`.

Notes:
- `#[ignore]` E2E tests are excluded by default and do not contribute to coverage.
- We will expand unit and non-ignored integration tests in the crates that matter most for correctness
  (chunk framing, manifest validation, encryption, ingest adapters).

## Reversibility

High. This adds a script and a convention; it does not change runtime behavior.

