JSONPlaceholder API Testing Framework

A simple and focused REST API testing framework built with REST Assured and JUnit 5 for testing the JSONPlaceholder API.

🎯 What This Framework Tests

6 JSONPlaceholder Resources

• /posts - 100 posts
• /comments - 500 comments
• /albums - 100 albums
• /photos - 5000 photos
• /todos - 200 todos
• /users - 10 users

HTTP Operations Tested

• ✅ GET /resource - Get all items
• ✅ GET /resource/1 - Get single item by ID
• ✅ POST /resource - Create new item
• ✅ PUT /resource/1 - Update existing item
• ✅ PATCH /resource/1 - Partially update item
• ✅ DELETE /resource/1 - Delete item
• ✅ Query Parameters - Filter resources (e.g., ?postId=1, ?userId=1)

🛠️ Technology Stack

• Java 11+
• Maven - Build management
• REST Assured 5.3.2 - API testing
• JUnit 5.10.0 - Test framework
• Allure 2.24.0 - Test reporting
• Jackson - JSON processing

📁 Simple Project Structure

jsonplaceholder-api-testing/
├── src/test/java/com/emmanuelarhu/
│   ├── base/
│   │   └── BaseTest.java           # Common test setup
│   ├── models/
│   │   ├── Post.java               # Post model
│   │   ├── User.java               # User model  
│   │   ├── Comment.java            # Comment model
│   │   ├── Album.java              # Album model
│   │   ├── Photo.java              # Photo model
│   │   └── Todo.java               # Todo model
│   └── tests/
│       ├── PostsTest.java          # Posts API tests
│       ├── UsersTest.java          # Users API tests
│       ├── CommentsTest.java       # Comments API tests
│       ├── AlbumsTest.java         # Albums API tests
│       ├── PhotosTest.java         # Photos API tests
│       └── TodosTest.java          # Todos API tests
├── pom.xml                         # Maven configuration
└── README.md                       # This documentation

⚡ Quick Start

1. Prerequisites

• Java 11+ installed
• Maven 3.6+ installed

2. Clone and Run

# Clone the repository
git clone <your-repo-url>
cd jsonplaceholder-api-testing

# Run all tests
mvn clean test

# Run specific test class
mvn test -Dtest=PostsTest

# Generate Allure report
mvn allure:serve

🧪 Test Examples

Posts API Tests

@Test
@DisplayName("GET /posts - Should return all 100 posts")
public void testGetAllPosts() {
    Response response = getRequest()
        .when()
        .get("/posts")
        .then()
        .statusCode(200)
        .body("$", hasSize(100))
        .body("[0].id", notNullValue())
        .body("[0].title", not(emptyString()))
        .extract().response();
    
    // Verify response time
    verifyResponseTime(response.getTime());
    
    // Convert to objects and verify
    Post[] posts = response.as(Post[].class);
    assertEquals(100, posts.length, "Should have exactly 100 posts");
    
    System.out.println("✅ Successfully retrieved " + posts.length + " posts");
}

Comments Filtering

@Test
@DisplayName("GET /comments?postId=1 - Should filter comments by post")
public void testFilterCommentsByPost() {
    Response response = getRequest()
        .queryParam("postId", 1)
        .when()
        .get("/comments")
        .then()
        .statusCode(200)
        .body("postId", everyItem(equalTo(1)))
        .extract().response();
    
    Comment[] comments = response.as(Comment[].class);
    for (Comment comment : comments) {
        assertEquals(1, comment.getPostId(), "All comments should belong to post 1");
    }
}

✅ What Each Test Verifies

For Every Endpoint:

1. HTTP Status Codes - Correct response codes (200, 201, 404)
2. Response Structure - Required fields are present and not empty
3. Data Types - Fields have correct data types
4. Response Time - Reasonable performance (under 5 seconds with warning)
5. Object Conversion - JSON can be converted to Java objects
6. Business Logic - Data makes sense (e.g., valid email formats, proper IDs)

Specific Validations:

• Posts: Title and body are not empty, userId exists
• Users: Email contains "@", name and username are not empty
• Comments: Email format, postId links to valid post
• Albums: Title exists, userId links to valid user
• Photos: URLs are not empty, albumId links to valid album
• Todos: Completion status is boolean, userId links to valid user

📊 Test Output Examples

✅ Successfully retrieved 100 posts
✅ Response time: 245ms
✅ Successfully retrieved post: Post{id=1, userId=1, title='sunt aut facere...'}
✅ Successfully retrieved 5 comments for post 1
✅ Successfully created new post with ID: 101
✅ Successfully updated post: Post{id=1, userId=1, title='Updated Post Title'}
✅ Successfully deleted post 1
✅ Correctly returned 404 for non-existent post

🔧 Key Features

Simple and Focused

• ✅ Clean, readable test code
• ✅ Clear test names and descriptions
• ✅ Simple assertions with helpful error messages
• ✅ Minimal setup required

Comprehensive Coverage

• ✅ All 6 JSONPlaceholder endpoints
• ✅ All HTTP methods (GET, POST, PUT, PATCH, DELETE)
• ✅ Query parameter filtering
• ✅ Error handling (404 for non-existent resources)

Built-in Validation

• ✅ HTTP status code verification
• ✅ Response structure validation
• ✅ Data type checking
• ✅ Performance monitoring
• ✅ Object conversion testing

Professional Reporting

• ✅ Allure test reports with detailed results
• ✅ Response time tracking
• ✅ Clear test descriptions
• ✅ Request/response logging

🚀 Running Different Test Scenarios

# Run all tests
mvn clean test

# Run specific endpoint tests
mvn test -Dtest=PostsTest
mvn test -Dtest=UsersTest
mvn test -Dtest=CommentsTest

# Run with verbose output
mvn test -X

# Generate and serve Allure report
mvn allure:serve

# Generate static Allure report
mvn allure:report

📋 Test Plan Summary

Functional Testing

• CRUD Operations - Create, Read, Update, Delete for all endpoints
• Data Validation - Verify response structure and data integrity
• Filtering - Test query parameters and filtering capabilities
• Error Handling - Test 404 responses for non-existent resources

Non-Functional Testing

• Performance - Monitor response times with warnings for slow responses
• Data Integrity - Verify relationships between resources (e.g., comments→posts)
• JSON Processing - Test object serialization/deserialization

📈 Allure Reports

The framework generates comprehensive Allure reports that include:

• ✅ Test Results Overview - Pass/fail statistics
• ✅ Test Case Details - Individual test execution details
• ✅ Request/Response Data - Full HTTP request and response logs
• ✅ Performance Data - Response time tracking
• ✅ Error Analysis - Detailed failure information

🎯 Success Criteria

All tests pass when:

• ✅ Correct number of resources returned (100 posts, 10 users, etc.)
• ✅ All required fields are present and not empty
• ✅ HTTP status codes are correct (200, 201, 404)
• ✅ Response times are under 5 seconds
• ✅ Data types match expectations
• ✅ Filtering works correctly
• ✅ CRUD operations complete successfully

👨‍💻 Author

Emmanuel Arhu
Quality Assurance Engineer & Developer

• 🌐 Website: emmanuelarhu.link
• 💼 LinkedIn: linkedin.com/in/emmanuelarhu
• 📧 Contact: emmanuelarhu.link/contact

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This framework demonstrates clean, simple API testing practices while providing comprehensive coverage of the JSONPlaceholder API. It's designed to be easy to understand, maintain, and extend.