How do I share a SimpleCov report?

SimpleCov writes `coverage/index.html` with a `coverage/assets/` folder next to it. Drag the whole `coverage/` directory into Comma, or PATCH `coverage/index.html` from CI. You get a URL that renders the file list and the line-by-line source view.

Why does the report look broken when I send just the HTML file?

The formatter's CSS, JavaScript and the DataTables bundle live in `coverage/assets/`. Detach the HTML from that folder and you get an unstyled table with no sorting and no source drill-down.

Can I publish coverage from GitHub Actions?

Yes — run the specs, then PATCH the same report id from the job. Use `if: always()` so a failing suite still publishes its coverage, which is usually the run you care about.

Does the line-by-line source view still work?

Yes. Report HTML renders with scripts enabled inside a sandboxed iframe, and the assets upload alongside the entry file with their references rewritten, so clicking through to a file's covered and missed lines behaves normally.

Can reviewers comment on an uncovered file?

Yes. Threads anchor to the rendered content, so 'this service object has no specs and it handles refunds' lands on that row and stays there across runs.

Share a SimpleCov coverage report

Every Ruby project has the same ritual. CI prints Line Coverage: 78.4%, someone screenshots it, and the actual report — the one that shows which lines are uncovered — never leaves the runner.

SimpleCov's default formatter writes a real, browsable artifact:

coverage/
  index.html
  assets/0.12.3/…      # css, js, DataTables, the sort widgets
  .last_run.json

Which is a folder, not a file. That is the whole reason it never gets shared.

Publish the folder

Drag coverage/ (or a zip of it) into the app:

index.html becomes the report body.
assets/ uploads alongside it with the relative references rewritten to the uploaded copies.
Scripts run inside a sandboxed iframe, so the group tabs, the sortable file table and the per-file source view all work.

From CI

# spec/spec_helper.rb
require "simplecov"
SimpleCov.start "rails"

bundle exec rspec

curl -fsS -X PATCH "https://commareports.com/api/v1/reports/$REPORT_ID" \
  -H "Authorization: Bearer $COMMA_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d "$(jq -n --rawfile html coverage/index.html \
        --arg title "Coverage — $GITHUB_SHA" '{title: $title, html: $html}')"

PATCHing one report id per repository keeps a single URL for "our coverage" and appends a revision per run — so a drop is a diff between two revisions instead of a number someone half-remembers from last sprint.

Wrap the publish step so it runs on failure too (if: always() on GitHub Actions, when: always on GitLab and CircleCI, post { always { … } } on Jenkins).

What review adds

Coverage arguments are never about the percentage. They are about which uncovered lines matter:

Anchored threads on the file or the line range — see commenting on HTML.
Revisions so a coverage cliff has a visible before and after.
Access per report — private, team, domain-gated, or named reviewers. See the sharing model.

Limits

Entry HTML: 5 MB. A monolith's file index can get close; SimpleCov groups help. Assets: 25 MB per file, 250 MB and 500 files total.
60 requests/minute per token.

Try it

Comma is free — unlimited reports, unlimited commenters, unlimited revision history.

Publish a coverage report →