$devvkit learn --librarie codecov:-coverage-in-ci-guide

Codecov: Coverage in CI Guide

[oss-stack][testing][coverage][ci]

Open Source

Install

# After running tests with coverage:
bash <(curl -s https://codecov.io/bash)
# or the unified uploader:
curl -Os https://uploader.codecov.io/latest/linux/codecov && chmod +x codecov

Codecov collects coverage reports from any test runner (Jest, pytest, cargo-tarpaulin...), visualizes them per file and line, and reports the delta on every pull request. The open source plan is free and unlimited for public repos: this is the easiest credibility win available to a new project.

The killer feature for maintainers is the patch check: a PR that drops coverage below your threshold fails, without a single line of test-policing code. Combined with badges on the README it converts "we test things" from a claim into a number.

Setup

Install the app· Codecov GitHub App + token in CI.

# Install app: github.com/apps/codecov
# Add CODECOV_TOKEN to repo secrets.

# CI step:
- run: npm test -- --coverage
- uses: codecov/codecov-action@v4
  with:
    token: ${{ secrets.CODECOV_TOKEN }}
    fail_ci_if_error: true

Upload

Local upload· Upload from anywhere.

# Bash uploader (legacy):
bash <(curl -s https://codecov.io/bash)

# Current unified uploader:
curl -Os https://uploader.codecov.io/v0.4/linux/codecov
chmod +x codecov
./codecov -t $CODECOV_TOKEN

# Python:
pip install codecov
codecov

Status Checks

Target and patch· Require minimum overall and delta coverage.

# codecov.yml:
coverage:
  status:
    project:
      default:
        target: 90%
        threshold: 1%
    patch:
      default:
        target: 80%
comment:
  layout: "reach, diff, flags, components"
  require_changes: true

Configuration

Badge· The README badge that proves the number.

[![codecov](https://codecov.io/gh/OWNER/REPO/branch/main/graph/badge.svg)](https://codecov.io/gh/OWNER/REPO)

# Also expose on the branch: 
# codecov.io/gh/OWNER/REPO/branch/main/graphs/tree.html