Parity Coverage JSON

parity-coverage.json is a language-neutral attribution format for ecosystems whose native coverage output does not include which test covered which line.

Use it when Clover or Cobertura can prove aggregate file coverage, but you also want matched-coverage and coverage-attribution.

Schema

{
  "version": 1,
  "globalPercent": 80,
  "files": [
    {
      "path": "src/formatCurrency.ts",
      "coveragePercent": 70,
      "totalExecutableLines": 10,
      "lines": [
        {
          "line": 1,
          "coveredBy": ["formatCurrency.test::coversPrimaryBehavior"]
        }
      ]
    }
  ]
}

Field	Required	Description
version	Recommended	Format version. Use 1.
globalPercent	Optional	Project-level coverage percentage from 0 to 100.
files[].path	Yes	Source path relative to the project root.
files[].coveragePercent	Recommended	All-test coverage percentage for the file.
files[].totalExecutableLines	Required for matched-coverage	Number of executable lines in the file.
files[].lines[].line	Yes	Executable line number.
files[].lines[].coveredBy	Yes	Test names that covered that line.

Configuration

coverage_xml: [.parity/per-test, parity-coverage.json, coverage-xml, clover.xml, cobertura.xml]

structure:
  - name: "Utilities"
    paths:
      source: "src"
      test: "tests"
    rules:
      - minimum-coverage:
          min: 70
      - matched-coverage:
          min: 40

JavaScript Converter Example

This minimal converter shows the shape a custom tool should produce. Real converters should read attribution from the runner, coverage library, or instrumentation layer available in the project.

import { writeFileSync } from 'node:fs'

const report = {
  version: 1,
  globalPercent: 80,
  files: [
    {
      path: 'src/formatCurrency.ts',
      coveragePercent: 70,
      totalExecutableLines: 10,
      lines: [
        {
          line: 1,
          coveredBy: ['formatCurrency.test::formats_cents']
        },
        {
          line: 2,
          coveredBy: [
            'formatCurrency.test::formats_cents',
            'checkout.integration.test::renders_total'
          ]
        }
      ]
    }
  ]
}

writeFileSync('parity-coverage.json', `${JSON.stringify(report, null, 2)}\n`)

Then run:

parity check --config=parity.yaml --format=json