Native API Testing in Pure Java (Java · HttpClient · JUnit · Allure)

A compact portfolio project that demonstrates protocol-level API testing without framework abstraction. It uses Java's built-in HttpClient, manual assertions, and a minimal custom JSON parser to show how HTTP requests and responses are handled under the hood.

Feature Under Test

This suite targets the JSONPlaceholder public API and focuses on Users:

• GET /users/{id} → validate status, headers, and parsed fields
• POST /users → validate create flow and echoed payload
• PUT /users/{id} → validate update flow
• DELETE /users/{id} → validate delete flow
• GET /invalidEndpoint → validate 404 handling

Highlights

• Plain Java HTTP via java.net.http.HttpClient — no RestAssured, no Spring
• Manual assertions to show what frameworks abstract away
• Custom minimal JSON parser (JsonParser) for protocol-level transparency
• OOP structure with UserService abstraction
• Allure reporting + structured logs

Tech Stack

• Java 17
• Maven
• JUnit 5
• Allure
• SLF4J + Logback

Quick Start

# Run tests
mvn test

# Generate Allure report
mvn allure:report

Open: target/site/allure-maven-plugin/index.html

Serve report locally:

mvn allure:serve

Example Tests

The following tests cover the full CRUD surface of the JSONPlaceholder Users API. Each test uses TestLogger to attach request/response details to the Allure report and ApiAssertions for readable, custom assertions:

@Test
void getUserById() throws IOException, InterruptedException {
    TestLogger.step("GET /users/1");
    ApiResponse<User> response = userService.getUserById(1);
    TestLogger.attach("response.user", String.valueOf(response.body()));

    ApiAssertions.assertStatusCode(response, 200);
    ApiAssertions.assertHeaderContains(response, "content-type", "application/json");
    assertUserBasics(response.body());
}

@Test
void createUser() throws IOException, InterruptedException {
    TestLogger.step("POST /users");
    User payload = buildUser("John Doe", "jdoe", "john@example.com");

    ApiResponse<User> response = userService.createUser(payload);

    ApiAssertions.assertStatusCode(response, 201);
    assertUserBasics(response.body());
}

@Test
void getMissingUser() throws IOException, InterruptedException {
    TestLogger.step("GET /users/999999");
    ApiResponse<User> response = userService.getUserById(999999);

    ApiAssertions.assertStatusCode(response, 404);
}

@Test
void deleteUser() throws IOException, InterruptedException {
    TestLogger.step("DELETE /users/1");
    ApiResponse<Void> response = userService.deleteUser(1);

    // Custom assertion handles 200 or 204 — both are valid DELETE responses
    ApiAssertions.assertStatusCodeIn(response, 200, 204);
}

assertUserBasics is a shared private helper that validates the three required fields (name, username, email) across multiple tests without duplication. assertStatusCodeIn handles cases where the server legitimately returns one of several valid status codes — a pattern frameworks like RestAssured implement internally but here is made explicit.

Project Structure

api-automation/
│
├── src/main/java/com/apiAutomation/
│   ├── client/                 # ApiClient + ApiResponse
│   ├── config/                 # Config (base URL)
│   ├── model/                  # User model
│   ├── service/                # UserService (API operations)
│   └── util/                   # JsonParser (minimal parser)
│
├── src/test/java/com/apiAutomation/
│   ├── client/                 # ApiClientTest + assertions + logging
│   └── util/                   # JsonParserTest
│
├── src/test/resources/
│   └── logback-test.xml         # Test logging config
│
├── pom.xml
└── README.md

Why No Jackson

This project intentionally avoids JSON libraries to demonstrate manual parsing and mapping basics.

JsonParser supports:

• Flat JSON objects only
• Manual type conversion (String, int, boolean)
• Simple Map serialization to JSON

Nested arrays/objects are intentionally skipped by design.

Test Output

• Allure results: target/allure-results/
• Surefire reports: target/surefire-reports/
• Log file: target/test-logs/test.log
• Allure HTML report: target/site/allure-maven-plugin/index.html