15 REST Assured Interview Questions: From Basic and Advanced

rest assured interview questions

Basic Rest Assured Interview Questions

  1. What is REST Assured?
    REST Assured is a Java DSL (Domain Specific Language) that simplifies the process of testing and validating RESTful web services. It provides a convenient way to send HTTP requests to a RESTful web service and verify the response. With REST Assured, testers and developers can write powerful, readable, and maintainable tests for their RESTful APIs, making it an essential tool in the modern testing landscape.
  2. Explain the concept of REST.
    REST, or Representational State Transfer, is an architectural style for designing networked applications. It uses a stateless, client-server communication model, where each request from the client contains all the information needed by the server to understand and process that request. RESTful applications use HTTP requests to perform CRUD operations (Create, Read, Update, Delete) on resources, which are identified by URIs (Uniform Resource Identifiers).
  3. Define JSON and its significance.
    JSON, which stands for JavaScript Object Notation, is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. Its significance lies in its simplicity and universality. JSON has become the de facto standard for data exchange in web applications, primarily because of its compatibility with most programming languages and its ability to represent complex data structures in a readable format.
  4. Which protocol do RESTful Web Services use?
    RESTful Web Services predominantly use the HTTP (Hypertext Transfer Protocol) for communication. HTTP provides a set of methods, such as GET, POST, PUT, DELETE, etc., that correspond to create, read, update, and delete operations, making it a natural choice for implementing RESTful services.
  5. Describe the “client-server architecture”.
    The client-server architecture is a computing model where the server hosts, delivers, and manages most of the resources and services to be consumed by the client. In this model: The client is responsible for the user interface and user experience, making requests and displaying the results or functionality. The server stores and retrieves data, processes client requests, and sends appropriate responses back to the client.
  6. What is a resource in REST?
    In REST, a resource refers to any object, data, or service that can be accessed by the client over the network. A resource is identified by a unique URI (Uniform Resource Identifier). For instance, in an online book store, each book, author, or category can be considered a resource, and they can be accessed and manipulated using specific URIs.
  7. Elaborate on REST Assured method chaining.
    Method chaining in REST Assured allows testers to combine multiple methods in a single line, enhancing code readability and maintainability. This is often seen in the form of given(), when(), and then() constructs. For example:
given().parameters("key", "value").when().get("/endpoint").then().statusCode(200);

This sequence sets up the request with parameters, makes a GET call to the specified endpoint, and then verifies that the response status code is 200.

  1. Why choose REST Assured over Postman for automation?
    While Postman is an excellent tool for manual API testing, REST Assured shines in the realm of automation. Here’s why:
  • Code Reusability: With REST Assured, common setups, and configurations can be reused across multiple tests.
  • Integration with Java: Being a Java library, REST Assured can be seamlessly integrated with Java-based testing frameworks like JUnit or TestNG.
  • Customizable Reports: REST Assured allows for generating detailed and customized reports, providing insights into test results.
  • Flexibility: REST Assured offers more flexibility in terms of test scripting, data-driven testing, and integrating with other tools in the CI/CD pipeline.

In essence, for those looking to automate their API testing, REST Assured provides a more robust and flexible solution compared to Postman.

Advanced Rest Assured Interview Questions

  1. How is method chaining implemented in REST Assured?
    Method chaining in REST Assured is a powerful feature that allows for a more concise and readable way to write tests. It’s implemented using the Fluent API design pattern, which returns the current object after every method call, allowing for the chaining of methods. This design ensures that the code remains clean, organized, and easy to understand. For instance, the sequence given().when().then() is a classic example of method chaining in REST Assured, where each method returns an instance that can call the next method in the chain.
  2. Demonstrate a code snippet using REST Assured for testing REST API.
    Certainly! Here’s a simple example that tests a GET request to retrieve a user’s details:
import static io.restassured.RestAssured.*;

public class GetUserDetailsTest {
    public void testGetUser() {
            .param("id", "12345")
            .body("name", equalTo("John Doe"));

In this snippet, we’re using REST Assured to send a GET request to https://api.example.com/users?id=12345 and then verifying that the response status is 200 and the user’s name is “John Doe”.

  1. What is JSON path in the context of REST Assured?
    JSON path in REST Assured is a mechanism to navigate and extract data from a JSON document. It’s similar to XPath for XML and provides a simple way to query JSON structures. With JSON path, you can easily extract values, evaluate JSON content, and perform validations. For instance, if you want to extract the name of a user from a JSON response, you can use the expression $.name where $ represents the root of the JSON document.
  2. Explain the concept of static import in Java and its use in REST Assured.
    Static import in Java allows for the importing of static members of a class directly, so you don’t need to qualify them with the class name. In the context of REST Assured, static imports simplify the code by importing commonly used methods directly. For example, instead of writing RestAssured.given(), with a static import, you can simply write given(). This makes the code more readable and concise, especially when chaining methods.
  3. Define serialization and deserialization in Java.
    Serialization in Java refers to the process of converting an object into a byte stream, which can then be saved to a file or sent over a network. Deserialization is the reverse process, where the byte stream is converted back into an object. This mechanism allows for the persistent storage and transmission of Java objects. In the context of REST APIs, serialization might be used to convert Java objects into JSON or XML format before sending them in a request, while deserialization would convert received JSON or XML data back into Java objects.
  4. Discuss the difference between path parameters and query parameters.
    Path parameters are part of the URL path and are used to identify a specific resource or resources. For example, in /users/123, 123 is a path parameter representing a user’s ID. On the other hand, query parameters are appended to the URL after a ? and are typically used to filter, sort, or provide additional information about a resource. For instance, in /users?type=admin, type=admin is a query parameter filtering users by type.
  5. Describe the request specification and response in Rest Assured.
    In REST Assured, the request specification allows you to define various aspects of an HTTP request, such as headers, parameters, body, and authentication details. It’s created using the given() method. The response, on the other hand, represents the HTTP response received after making a request. It provides methods to extract data, verify status codes, and validate response content. The response can be obtained using methods like get(), post(), and put(), and its content can be validated using the then() method.
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In today’s digital age, proficiency in tools like REST Assured is invaluable. As web services become integral to businesses, ensuring their reliability is paramount. With the right knowledge and preparation, especially around pivotal REST Assured interview questions, professionals can not only enhance their skill set but also become indispensable assets to their organizations. Stay informed, stay ahead, and harness the power of REST Assured to its fullest.

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