Find missing tests

❌ Coverage percentage targets let untested code slip through code review. Post-factum test additions cost you more and miss the context.

✅ Undercover integrates with your CI and local workflow to warn on all methods, classes, blocks and branches that were changed without test coverage. Catch them early, prevent bugs and ship with confidence.

Undercover GitHub comments
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These leading Ruby engineering teams review test coverage with undercover

How it works

Stop focusing on getting to 100% test coverage.
Detect when changed code is untested before it's deployed.

Actionable review comments

Each class, method or block that's been changed without tests receives a check annotation including detailed information about what's missing and where: line coverage or branch coverage, plus respective line numbers and number of hits.

Worried about too many comments? You won't receive more than one comment per method, because Undercover understands code structure and only works with the current diff.

Undercover GitHub comment

Status checks

No untested changes in the diff? Merge away. Otherwise, it's up to you to configure whether a passing check is required to merge. If you decide to make it required, selected annotations can still be muted with SimpleCov's :nocov: comment syntax to go green and fix coverage later.

Commit status check from Undercover

Test coverage summary

Lists file names, class/method names and coverage information for a commit or pull request. Methods that cause the check to fail are flagged with a warning emoji (⚠️) - one or more line or branch appears in the PR diff and has to be fixed. All others provide a refactoring opportunity for you to improve the test coverage if it's low somewhere outside of the diff.

Check summary when coverage fails

Choose your setup

Install Undercover's hosted GitHub App or explore the Ruby gems family

Undercover GitHub App

$49 per month

VAT not included, try it free for 14 days

Fully-featured GitHub App code review integration with quick setup for your organization. Included features:

✅ Coverage warnings as GitHub annotations (via GitHub Checks)

✅ Diff coverage summary view for each commit

✅ Branch coverage support

✅ Unlimited builds for private and public repos

✅ Unlimited users

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Open Source

The UndercoverCI project and related Ruby gems are entirely open-source and free to use locally and in your CI/CD workflows.

If a hosted and convenient GitHub App integration is not for you, check out these links to get started:

Why Undercover

Read more about Ruby code coverage and unit testing strategy

The purpose of branch coverage is to check whether every conditional branch in a given line of code has been tested and Ruby has this feature since 2.5. Ruby’s simplecov can report branch coverage too and now so does undercover with the new 0.4 release!
Today, I’m launching UndercoverCI— a CI robot who protects your Ruby codebase from untested code changes. Take a moment to learn why you should add it to your team’s code review workflow. Adding UndercoverCI to your code review workflow will prevent untested code changes from slipping into production without anyone noticing.
So what is the value of coverage analysis again? Well it helps you find which bits of your code aren't being tested. It's worth running coverage tools every so often and looking at these bits of untested code. Do they worry you that they aren't being tested?

Find untested code in your PRs

Free for individuals and open-source repositories. Organization plans start at $49 per month with a free 14-day trial.

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