SimpleCov Gate

A GitHub Action that fails the build when the total line coverage reported by SimpleCov drops below a minimum threshold.

It is a composite action running a single dependency-free Ruby script on the runner's preinstalled Ruby — no setup-ruby, no gems to install, no container to pull. It starts in milliseconds.

Usage

Run your test suite with SimpleCov enabled, then add the gate:

permissions:
  contents: read
  checks: write # lets the action publish its "SimpleCov Gate" check run

steps:
  - uses: actions/checkout@v4

  - name: Run tests
    run: bundle exec rake test

  - name: Enforce coverage
    uses: srozen/simplecov-gate@v1
    with:
      minimum-coverage: 95

The action reports the covered percentage and the minimum in the job log and in the step summary, emits an ::error annotation when the gate fails, and publishes the verdict as a dedicated SimpleCov Gate check run listed alongside your other checks on the pull request.

The check run needs the checks: write permission shown above; without it the action prints a warning and the gate still passes or fails normally. Set github-token: "" to disable the check run entirely.

Inputs

Input	Required	Default	Description
minimum-coverage	yes	—	Minimum required total line coverage, in percent (e.g. 90 or 99.5)
coverage-path	no	coverage	Directory containing the SimpleCov report
github-token	no	github.token	Token used to publish the check run; empty string disables it

How it works

The action reads coverage.json, which SimpleCov writes to its coverage directory by default since version 1.0, and takes the exact total line coverage SimpleCov reported (total.lines.percent). On older SimpleCov versions it gracefully falls back to .last_run.json, covering both the result.line (0.18+) and result.covered_percent (pre-0.18) formats.

The percentage is floored to two decimals — never rounded up — mirroring SimpleCov's own strictness, so 94.999% does not pass a 95% gate.

Development

bundle install
bundle exec ruby test/simplecov_gate_test.rb

This repository dogfoods itself: CI runs the test suite and then gates it with this very action at 100% line coverage.