Track API Coverage with wdio-openapi-service

When running API tests, how do you know if your test suite actually covers all the endpoints defined in your OpenAPI specification? wdio-openapi-service answers this by tracking every API request during your WebdriverIO test runs and matching them against your OpenAPI/Swagger spec.

Why API Coverage Matters

You might have hundreds of tests passing, but if they only exercise 60% of your API surface, you have blind spots. This service gives you a clear picture:

Feature	Description
Complete Tracking	Tracks all API requests made during test runs
Spec Matching	Matches requests against OpenAPI 3.0 and Swagger 2.0
Method Breakdown	Coverage by HTTP method (GET, POST, PUT, DELETE)
Path Normalization	Converts `/users/123` to `/users/{id}` automatically
CI/CD Ready	Works with GitHub Actions, Jenkins, CircleCI

Installation

npm install --save-dev wdio-openapi-service

Quick Start

Step 1: Add the Service

Add the service to your wdio.conf.ts:

export const config = {
  services: [
    ['openapi', {
      openApiPath: './openapi.yaml',
      outputPath: './reports/api-coverage.json'
    }]
  ]
}

Step 2: Use the API Client

import { apiClient } from 'wdio-openapi-service'

describe('API Tests', () => {
  it('should retrieve user data', async () => {
    const response = await apiClient.get('https://api.example.com/users/1')
    expect(response.status).toBe(200)
  })
})

Step 3: Check Your Coverage Report

After running tests, check ./reports/api-coverage.json:

{
  "summary": {
    "totalEndpoints": 7,
    "testedEndpoints": 5,
    "untestedEndpoints": 2,
    "coveragePercentage": 71.43
  },
  "methodCoverage": {
    "GET": {"total": 4, "tested": 3, "percentage": 75},
    "POST": {"total": 1, "tested": 1, "percentage": 100},
    "PUT": {"total": 1, "tested": 1, "percentage": 100},
    "DELETE": {"total": 1, "tested": 0, "percentage": 0}
  }
}

Configuration Options

Option	Type	Default	Description
`openApiPath`	string	Auto-detected	Path to your OpenAPI spec file
`outputPath`	string	`./api-coverage-report.json`	Where to save the report
`logLevel`	string	`info`	Logging level
`enableDynamicPatternLearning`	boolean	`true`	Learn patterns from requests
`endpointPatternFile`	string	-	Custom pattern rules file

Path Normalization

Path normalization converts dynamic paths like /users/123 to template paths like /users/{id}. This works through three mechanisms:

OpenAPI-based — Paths from your spec are used as templates
Custom patterns — Define regex patterns for specific endpoints
Dynamic learning — The service auto-detects patterns from your API calls

Custom Pattern Example

services: [
  ['openapi', {
    openApiPath: './openapi.yaml',
    customPatterns: [
      {
        pattern: new RegExp('/users/\\d+'),
        template: '/users/{id}',
        priority: 100
      }
    ]
  }]
]

CI Integration

# GitHub Actions
jobs:
  api-coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
      - run: npm ci
      - run: npx wdio run wdio.conf.ts
      - uses: actions/upload-artifact@v4
        with:
          name: api-coverage
          path: ./reports/api-coverage.json

For the full documentation, visit the GitHub repo.

Have questions about API coverage tracking? Feel free to reach out or open an issue on GitHub.