Integration of Rest Assured with JUnit 4

  

To integrate RestAssured with JUnit 4 for API testing, you can follow these steps:

Overview

• RestAssured: A Java DSL for testing REST services.

• JUnit 4: A popular unit testing framework for Java.

Integration Workflow

• Add RestAssured and JUnit 4 dependencies.
• Write test cases using JUnit 4 annotations (@Test, @Before, etc.).
• Use RestAssured to make HTTP requests and validate responses.

1. Maven Dependencies

<dependencies>
    <!-- RestAssured -->
    <dependency>
        <groupId>io.rest-assured</groupId>
        <artifactId>rest-assured</artifactId>
        <version>5.4.0</version>
        <scope>test</scope>
    </dependency>

    <!-- JUnit 4 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>

    <!-- JSON path (optional but useful) -->
    <dependency>
        <groupId>io.rest-assured</groupId>
        <artifactId>json-path</artifactId>
        <version>5.4.0</version>
    </dependency>
</dependencies>

2. Simple GET API Test Example

import io.restassured.RestAssured;
import io.restassured.response.Response;
import org.junit.Before;
import org.junit.Test;

import static io.restassured.RestAssured.*;
import static org.hamcrest.Matchers.*;

public class APITest {

    @Before
    public void setup() {
        RestAssured.baseURI = "https://jsonplaceholder.typicode.com";
    }

    @Test
    public void testGetUser() {
        given().
            log().all().
        when().
            get("/users/1").
        then().
            log().all().
            assertThat().
            statusCode(200).
            body("id", equalTo(1)).
            body("username", notNullValue());
    }

    @Test
    public void testGetInvalidUser() {
        given().
            log().all().
        when().
            get("/users/9999").
        then().
            log().all().
            assertThat().
            statusCode(404);
    }
}

3. Explanation of Code

Section	Description
@Before	Sets the base URI for all API requests.
given()	Prepares the request (params, headers, etc.).
when()	Specifies the request type (GET/POST/PUT/DELETE).
then()	Asserts the response: status, body content, etc.
log().all()	Logs request/response details to console (for debugging).

4. Run the Tests

You can run these tests using:

• Eclipse/IntelliJ (right-click → Run as JUnit Test)

• Maven CLI:

mvn test

5. Important Points:

• Externalize base URLs using config files or environment variables.

• Use @BeforeClass for expensive setups.

• Use assertions to validate headers, response time, etc.

• Use POJOs (Plain Old Java Objects) for complex JSON validation with RestAssured + Gson or Jackson.