Java RestAssured API Testing Framework

Enterprise-grade REST API test automation framework built with Java, RestAssured, and TestNG. Demonstrates production-level patterns used in fintech/payments testing environments.

src/test/
├── java/com/rajTestAutomation/
│   ├── base/           # BaseTest - RequestSpec setup, auth, logging
│   ├── models/         # POJO models (PaymentRequest, PaymentResponse)
│   ├── tests/          # Test classes (PaymentAPITests, AuthAPITests)
│   └── utils/          # ApiUtils - reusable GET/POST/PUT/DELETE helpers
├── resources/
│   ├── config.properties  # Environment configs (base URL, credentials)
│   └── schemas/           # JSON schemas for contract validation
├── pom.xml
└── testng.xml

• Page Object Model equivalent for APIs — BaseTest + RequestSpecBuilder
• JSON Schema Validation — contract testing for every response
• Allure Reports — visual test reports with request/response details
• Parameterized Tests — data-driven via TestNG DataProvider
• Negative Testing — 400/401/404/422 response validation
• Idempotency Testing — duplicate payment detection (critical for fintech)
• CI/CD — GitHub Actions runs on every push/PR

• Payment initiation (POST /payments)
• Payment status retrieval (GET /payments/{id})
• Authentication flows (OAuth2 token validation)
• ISO 20022 / PSD2 compliance field validation
• Contract testing via JSON schema
• Negative: invalid IBAN, missing fields, duplicate transactions

# Run all tests
mvn clean test

# Run with specific suite
mvn clean test -Dsurefire.suiteXmlFiles=testng.xml

# Generate Allure report
mvn allure:serve

Built this framework pattern at Rabobank for validating iDEAL-to-Wero payment migration APIs handling 500K+ daily transactions. Key design decisions: RequestSpecBuilder centralises auth so tests stay clean; JSON schema validation catches contract breaks before they reach production; idempotency tests specifically prevent double-charge scenarios.

By Rajasekhar Narisetti — Senior Test Automation Engineer | Utrecht, NL