Tutorials123: API Testing using Rest Assured

What is a DELETE API?

A DELETE API is an HTTP method used to remove a resource from a server.
It is part of the standard CRUD operations (Create, Read, Update, Delete).
Example scenario: If your API has a list of users, a DELETE request to /users/5 would remove the user with ID 5.

Key Points:

DELETE requests usually don’t return a body, but sometimes may return a confirmation message.
After a DELETE operation, the resource should no longer exist.
The server typically returns:

Status 200 (OK) if deletion is successful and a response body is returned.

Status 204 (No Content) if deletion is successful but no content is returned.

Status 404 (Not Found) if the resource does not exist.

How to Test a DELETE API in Rest Assured

Testing a DELETE API is similar to other HTTP methods:

Set the Base URI and Endpoint: Specify the API URL and the resource to delete.
Send the DELETE Request: Make a DELETE call to the resource endpoint.
Validate the Response:

Check the HTTP status code (200, 204, or 404 depending on the case).

Optionally, check response headers (like Content-Type).

Optionally, verify response body if the API sends a confirmation message.

Verify Deletion:

Perform a GET request on the same resource to ensure it is no longer available (should return 404).

To test a DELETE API using Rest Assured in Java, you follow a standard procedure:

API used for DELETE operation:

DELETE https://reqres.in/api/users/2

This would delete user with ID 2.

Steps to Test DELETE API via Rest Assured:

Set the Base URI
Specify the Endpoint (example: /users/2)
Use given() to prepare request
Use .when().delete() to send the request
Use .then() to validate the response (status code, etc.)

Expected Response from `https://reqres.in/api/users/2`:

The ReqRes API will respond with HTTP status code 204 No Content which indicates successful deletion, but no body is returned.

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>io.rest-assured</groupId>
        <artifactId>rest-assured</artifactId>
        <version>5.4.0</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20230227</version>
    </dependency>
</dependencies>

Java Code using Rest Assured:

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

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

public class DeleteUserTest {

    public static void main(String[] args) {

        // Step 1: Set Base URI
        RestAssured.baseURI = "https://reqres.in/api";

        // Step 2: Perform DELETE request and validate
        Response response = given()
                                .when()
                                .delete("/users/2") // Endpoint
                                .then()
                                .statusCode(204) // Assert expected status code
                                .extract().response();

        // Step 3: Print response for debugging (though it should be empty)
        System.out.println("Status Code: " + response.getStatusCode());
        System.out.println("Response Body: '" + response.getBody().asString() + "'");
    }
}

Code explanation:

1. Set the base URI

2. Perform delete request and validate the response server code

3. Print the server code and response body

Just to Inform:

statusCode(204) ensures deletion is successful.
The response body should be empty (""), as per REST standard for DELETE.

How to Test DELETE API by Rest Assured

Steps to Test DELETE API via Rest Assured:

Expected Response from https://reqres.in/api/users/2:

Expected Response from `https://reqres.in/api/users/2`: