How to Test a Single Response Header by Rest Assured

 

To test a single response header in a GET API using Rest Assured in Java, you can follow these steps:

We want to:

• Send a GET request to https://reqres.in/api/users?page=2

• Extract and validate a specific response header (example: Content-Type)
  
  
  

What is a Response Header?

A response header provides metadata about the server response. Common headers include:

• Content-Type

• Content-Encoding

• Date

• Server

• Connection

Steps in Rest Assured

• Set the base URI
• Send a GET request
• Extract the specific header
• Validate it using assertion

Sample Java Code Using Rest Assured

import io.restassured.RestAssured;
import io.restassured.response.Response;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.equalTo;

public class GetResponseHeaderTest {

    public static void main(String[] args) {
        
        // Step 1: Set base URI
        RestAssured.baseURI = "https://reqres.in";

        // Step 2: Send GET request and get response
        Response response = RestAssured
                .given()
                .when()
                .get("/api/users?page=2")
                .then()
                .extract()
                .response();

        // Step 3: Print and verify a single header, e.g. Content-Type
        String contentType = response.getHeader("Content-Type");
        System.out.println("Content-Type header is: " + contentType);

        // Step 4: Assert the header
        assertThat("Header validation failed", contentType, equalTo("application/json; charset=utf-8"));
    }
}

Explanation:




• getHeader("Content-Type") fetches the value of the specified header.

• assertThat(..., equalTo(...)) checks if the header value is as expected.

Maven Dependency:

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