Bun test coverage

Skill secondsky/claude-skills/plugins/bun/skills/bun-test-coverage

Production-ready skills for Claude Code CLI - Cloudflare, React, Tailwind v4, and AI integrations

Install

npx -y skills add secondsky/claude-skills --skill bun-test-coverage

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What its author says it does

Copied from the file, not written here

Use for test coverage with Bun, --coverage flag, lcov reports, thresholds, and CI integration.

The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

3.3 KB, 829 tokens by cl100k_base, as published. Nobody here has run it

Bun Test Coverage

Bun has built-in code coverage reporting without additional dependencies.

Enabling Coverage

# Enable coverage
bun test --coverage

# With threshold (fail if below)
bun test --coverage --coverage-threshold 80

Configuration in bunfig.toml

[test]
coverage = true
coverageThreshold = 0.8  # 80% minimum
coverageDir = "./coverage"

# Patterns to ignore
coverageSkipTestFiles = true

Coverage Output

------------------|---------|---------|-------------------
File              | % Funcs | % Lines | Uncovered Line #s
------------------|---------|---------|-------------------
All files         |   85.71 |   89.23 |
 src/index.ts     |  100.00 |  100.00 |
 src/utils.ts     |   75.00 |   82.35 | 23-25, 41-43
 src/api.ts       |   80.00 |   85.00 | 67, 89-92
------------------|---------|---------|-------------------

Coverage Reporters

# Default console output
bun test --coverage

# Generate lcov report
bun test --coverage --coverage-reporter=lcov

# Multiple reporters
bun test --coverage --coverage-reporter=text --coverage-reporter=lcov

Available Reporters

Reporter	Output
`text`	Console table (default)
`lcov`	`coverage/lcov.info` for CI tools
`json`	`coverage/coverage.json`

Coverage Thresholds

Set minimum coverage requirements:

# Fail if coverage < 80%
bun test --coverage --coverage-threshold 80

# Per-metric thresholds in bunfig.toml

[test]
coverage = true
coverageThreshold = {
  lines = 80,
  functions = 75,
  branches = 70
}

Excluding Files

[test]
coverage = true

# Skip test files from coverage
coverageSkipTestFiles = true

# Patterns to exclude
coverageIgnore = [
  "**/*.test.ts",
  "**/fixtures/**",
  "**/mocks/**"
]

CI Integration

GitHub Actions

- name: Run tests with coverage
  run: bun test --coverage --coverage-reporter=lcov

- name: Upload coverage to Codecov
  uses: codecov/codecov-action@v5
  with:
    files: ./coverage/lcov.info

Output Directory

# Custom output directory
bun test --coverage --coverage-dir=./reports/coverage

Programmatic Coverage

import { test, expect } from "bun:test";

// Get coverage data programmatically
const coverage = Bun.coverage;

// Access after tests complete
process.on("exit", () => {
  console.log(coverage.getCoverageData());
});

Common Errors

Error	Cause	Fix
`Coverage threshold not met`	Coverage below threshold	Increase test coverage
`No coverage data`	Files not executed	Check test includes file
`lcov not found`	Missing reporter	Add `--coverage-reporter=lcov`

Best Practices

Set realistic thresholds - Start at 60%, increase gradually
Exclude generated files - Mock files, type definitions
Focus on critical paths - Business logic over boilerplate
Run in CI - Prevent coverage regression

When to Load References

Load references/reporters.md when:

Custom reporter configuration
CI/CD integration details
Codecov/Coveralls setup