What formats can I export my coverage reports in?

The skill supports HTML for human reading, as well as LCOV, JSON, Cobertura, and Plain Text for programmatic analysis or tool integration.

Does this work with cargo-nextest?

Absolutely. You can run 'cargo llvm-cov nextest' to leverage nextest's parallel execution for significantly faster coverage generation.

What are the requirements for using this skill?

You need to have Rust installed, along with the cargo-llvm-cov binary and the llvm-tools-preview component via rustup.

How do I fail a CI build if coverage is too low?

You can use the --fail-under-lines or --fail-under-functions flags followed by your desired percentage threshold to trigger a non-zero exit code.

Can I use this for branch coverage?

Yes, branch coverage is supported but requires the Rust nightly toolchain and the --branch flag during execution.

Rust Code Coverage (cargo-llvm-cov)

Name: Rust Code Coverage (cargo-llvm-cov)
Author: laurigates

bylaurigates

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Security & Testing

Generates precise Rust code coverage reports using LLVM-based instrumentation and integrates with CI/CD pipelines.

About

This Claude Code skill empowers developers to measure, visualize, and enforce code coverage within Rust projects using the cargo-llvm-cov tool. It provides a comprehensive suite of commands for generating various report formats—including HTML, LCOV, JSON, and Cobertura—while offering seamless integration with CI platforms like GitHub Actions, Codecov, and Coveralls. By leveraging LLVM's source-based coverage, it ensures high accuracy and supports advanced features like branch coverage (on nightly) and parallel test execution through cargo-nextest, making it essential for maintaining high-quality, well-tested Rust codebases.

Key Features

Source-based LLVM coverage instrumentation for high precision
CI/CD integration with configurable coverage thresholds to fail builds
Support for workspace-wide coverage and specific crate filtering
3 GitHub stars
Multiple output formats including interactive HTML, LCOV, and Cobertura XML
Seamless integration with cargo-nextest for faster, parallel test runs

Use Cases

Measuring and visualizing test coverage locally via interactive HTML reports
Enforcing minimum coverage requirements in automated pull request workflows
Integrating coverage data with third-party dashboards like Codecov and Coveralls

About

Key Features

Source-based LLVM coverage instrumentation for high precision
CI/CD integration with configurable coverage thresholds to fail builds
Support for workspace-wide coverage and specific crate filtering
3 GitHub stars
Multiple output formats including interactive HTML, LCOV, and Cobertura XML
Seamless integration with cargo-nextest for faster, parallel test runs

Use Cases

Measuring and visualizing test coverage locally via interactive HTML reports
Enforcing minimum coverage requirements in automated pull request workflows
Integrating coverage data with third-party dashboards like Codecov and Coveralls