Self-Hosted Coverage Service

Track Your Test Coverage

A self-hosted test coverage tracking service. Upload coverage data from CI, view per-file reports, compare branches, and embed badges in your README.

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Features

Everything you need to track and improve test coverage

Coverage Tracking

Upload coverage data from your CI pipeline. View line-by-line coverage for every file with highlighted hit/miss indicators.

Badge Generation

Embed dynamic SVG coverage badges in your README. Badges auto-update with every build and use color coding for quick status checks.

Branch Comparison

Compare coverage between branches. See exactly which files gained or lost coverage in a pull request before merging.

Quick Start

Get coverage tracking running in 4 steps

Sign up & create a project

Create an account, then add a new project from the dashboard. You'll receive an API token for uploading coverage data.

Add the gem to your Gemfile

# Gemfile
group :test do
  gem "simplecov", require: false
  gem "simplecov-japan-voyage", require: false
end

Then run bundle install.

Configure test_helper.rb

# test/test_helper.rb (or spec/spec_helper.rb)
require "simplecov"
require "simplecov_japan_voyage"

SimpleCov.start "rails" do
  add_filter "/test/"
  add_filter "/config/"
end

SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new([
  SimpleCov::Formatter::HTMLFormatter,
  SimpleCovJapanVoyage::Formatter
])

The formatter reads COVERAGE_TOKEN from ENV automatically. When absent (local dev), it skips the upload silently.

Set COVERAGE_TOKEN in CI

# .github/workflows/ci.yml
- name: Run tests
  env:
    RAILS_ENV: test
    COVERAGE_TOKEN: ${{ secrets.COVERAGE_TOKEN }}
  run: bin/rails test

Add the project's API token as a repository secret in your CI provider. The gem defaults to https://coverage.japanvoyage.jp.

API Reference

RESTful endpoints for coverage data

POST /api/v1/builds

Upload a coverage build. Requires token authentication.

Authentication

Authorization: Bearer <COVERAGE_TOKEN>

Request Body (JSON)

{
  "commit_sha": "abc123",
  "branch": "main",
  "commit_message": "Add tests",
  "commit_author": "dev@example.com",
  "covered_percent": 87.5,
  "lines_covered": 1750,
  "lines_missed": 250,
  "lines_total": 2000,
  "ci_service": "github_actions",
  "ci_build_url": "https://github.com/...",
  "files": [
    {
      "file_path": "app/models/user.rb",
      "covered_percent": 95.0,
      "lines_covered": 19,
      "lines_missed": 1,
      "lines_total": 20,
      "line_coverage": [1, 1, null, 0, 1, ...]
    }
  ]
}

Response (201 Created)

{
  "id": 42,
  "covered_percent": 87.5,
  "coverage_delta": 1.2,
  "url": "https://coverage.japanvoyage.jp/projects/my-app/builds/42"
}

GET /api/v1/status/:badge_token

Get the latest coverage status for a project. Public, no authentication required.

Response (200 OK)

{
  "project": "my-app",
  "branch": "main",
  "covered_percent": 87.5,
  "lines_covered": 1750,
  "lines_missed": 250,
  "lines_total": 2000,
  "commit_sha": "abc123",
  "created_at": "2026-02-26T10:00:00Z"
}

GET /badges/:badge_token.svg

Returns a dynamic SVG coverage badge. Public, no authentication required. Cached for 5 minutes.

Badge Colors

90%+ (bright green) 80-89% (yellow-green) 70-79% (yellow) 60-69% (orange) <60% (red)

Badge Examples

Add a coverage badge to your project README

Markdown

![Coverage](https://coverage.japanvoyage.jp/badges/YOUR_BADGE_TOKEN.svg)

HTML

<img src="https://coverage.japanvoyage.jp/badges/YOUR_BADGE_TOKEN.svg" alt="Coverage">

Configuration

Environment variables for the SimpleCov formatter

Variable	Required	Default	Description
`COVERAGE_TOKEN`	Yes	—	Project API token from the dashboard. Upload is skipped when absent.
`COVERAGE_URL`	No	`https://coverage.japanvoyage.jp`	Override the coverage service URL (e.g. for self-hosted instances).

Ready to track your coverage?

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