API Testing Part1

   

   API Testing Part 1

 

  1.       What is an API?

An API (Application Programming Interface) is a set of rules and protocols for building and integrating software applications. It defines the way that different software systems interact and allows for communication between them. An API allows a developer to access the functionality or data of an application or service, enabling them to build software that relies on that functionality or data.

Examples of API

There are many examples of APIs, some common ones include:

1. Social Media APIs: such as the Facebook Graph API, which allows developers to access data from Facebook, like user profiles and friends lists.
2. Payment APIs: such as the Stripe API, which allows developers to integrate online payment functionality into their applications.
3. Weather APIs: such as OpenWeatherMap API, which allows developers to access current weather data and forecasts for a specific location.
4. Maps APIs: such as the Google Maps API, which allows developers to add maps and location-based functionality to their applications.
5. E-commerce APIs: such as Amazon Product Advertising API, which allows developers to access information about products and sellers on the Amazon marketplace.
6. Logistics and Delivery APIs: such as FedEx API and UPS API, which allow developers to track packages, calculate shipping costs, and print shipping labels from within their own applications.

These are just a few examples of the many types of APIs that are available for developers to use.

2.       What are main differences between API and Web Service?

API (Application Programming Interface) and Web Service are often used interchangeably, but there are some subtle differences between the two.

1. API is a set of protocols and tools for building software and applications, while a Web Service is a specific kind of API that can be accessed over the internet using standard web protocols.
2. API is a general term that can be applied to any kind of application programming interface, whether it is web-based or not. A Web Service, on the other hand, is a specific type of API that is built using web technologies and can be accessed over the internet.
3. API is a way for different software systems to communicate with each other, while a Web Service is a way for different software systems to communicate over the internet.
4. API can be either Open or closed, while Web Service is generally open, and can be accessed by anyone who has the proper credentials.

In summary, API is a broader term that can include any kind of interface for building software, while a web service is a specific type of API that is accessible over the internet.

3.       What are the Limits of API Usage?

APIs (Application Programming Interfaces) typically have usage limits to ensure fair usage and prevent abuse. These limits can include:

1. Request limits: This is the maximum number of requests that can be made to the API within a specific time period. For example, an API may limit the number of requests to 100 per minute.
2. Burst limits: This is the maximum number of requests that can be made in a short period of time, usually a few seconds. This is to prevent a sudden spike in traffic from overwhelming the API server.
3. Concurrent request limits: This is the maximum number of requests that can be made at the same time. This is to prevent an excessive number of requests from overloading the server.
4. Data limits: This is the maximum amount of data that can be returned from the API in a single request. This helps to prevent large amounts of data from being returned and overwhelming the client.
5. Authentication and Authorization: Most of the APIs are protected with some sort of authentication and authorization mechanism, usually through API keys, tokens, or OAuth.
6. IP Whitelisting: Some APIs only allows request from specific IP addresses to prevent unauthorized access.

These limits are usually put in place to ensure that the API remains available and responsive for all users, and also to prevent abuse and overuse of the API. Some providers have different levels of access, so the limits will be different depending on the plan you choose.

4.       What are some architectural styles for creating a Web API

There are several architectural styles for creating a web API, some of the most common include:

1. REST (Representational State Transfer): This is a popular architectural style for building web APIs, as it emphasizes the use of simple, standard HTTP methods (such as GET, POST, PUT, and DELETE) to perform operations on resources.
2. SOAP (Simple Object Access Protocol): This is an older architectural style for building web APIs that uses XML for message formatting and can be carried over different transport protocols such as HTTP and SMTP.
3. RPC (Remote Procedure Call): This architectural style is based on the idea of calling remote procedures or methods as if they were local. This style is not as widely used as REST or SOAP, but it can be useful in certain situations where a more procedural approach is required.
4. GraphQL: This is a query language and runtime for building APIs, it allows the client to define the structure of the data required, and the server will return exactly that.
5. gRPC: This is a high-performance, open-source framework for building remote procedure call (RPC) APIs, gRPC uses the Protocol Buffer data serialization format and the gRPC protocol to create high-performance, highly-scalable APIs.

Each architectural style has its own set of advantages and disadvantages, and the choice of which one to use will depend on the specific requirements of the API and the use case it is intended for.

5.       Who can use a Web API

Web APIs (Application Programming Interfaces) can be used by any developer or organization that wants to integrate functionality or data from an external source into their own software or application. This can include:

1. Independent Developers: Individual developers can use web APIs to add new functionality or data to their own projects, such as adding a map or weather forecast feature to a mobile app.
2. Startups: Startups can use web APIs to access data and functionality from established companies and platforms, such as using the Stripe API to process payments.
3. Enterprises: Large organizations can use web APIs to integrate data and functionality from different systems within the organization, or to connect with external partners and suppliers.
4. Research and education: Researchers and students can use web APIs to access data and functionalities to support their research and studies.
5. Government organizations: Government organizations can use web APIs to make data and services accessible to the public.

It's important to note that most of the web APIs have some sort of terms of use, and usage limits which should be read carefully before using them. Also, some of the APIs are public and can be accessed by anyone, while others are private and require authentication and authorization to access them.

6.       What is API Testing

API Testing is a type of software testing that involves testing application programming interfaces (APIs) to ensure they function correctly and meet performance and security expectations. API testing can be done at different levels, including:

1. Unit Testing: This type of testing focuses on individual units or components of the API, such as individual functions or methods.
2. Integration Testing: This type of testing checks how well the API integrates with other components or systems.
3. Functional Testing: This type of testing checks that the API functions as intended and meets the requirements specified in the documentation.
4. Performance Testing: This type of testing checks the API's performance characteristics, such as response time and throughput.
5. Security Testing: This type of testing checks the API's security measures and validates that the API is protected against common security threats such as SQL injection, cross-site scripting, and others.

API testing can be automated or performed manually, and it can be done by developers or by a dedicated testing team. The testing process typically involves creating test cases, executing the tests, and comparing the results against expected outcomes. The main goal of API testing is to identify and fix any bugs, performance issues, or security vulnerabilities before the API is released to production.

7.       What are the advantages of API Testing

API Testing offers several advantages, including:

1. Early detection of bugs: By testing the API before it is integrated into a larger system, developers can identify and fix bugs early in the development process, reducing the risk of costly and time-consuming issues later on.
2. Improved quality: By thoroughly testing the API, developers can ensure that it meets the requirements and functions correctly, resulting in a higher-quality product.
3. Increased efficiency: Automated testing can save time and increase efficiency by automating repetitive tasks and reducing manual testing efforts.
4. Better security: API testing can help identify and mitigate security vulnerabilities, making the final product more secure.
5. Reduced costs: By identifying and fixing issues early in the development process, API testing can help reduce the overall cost of development by avoiding costly delays and rework.
6. Improved collaboration: API testing enables developers to work together more effectively by providing clear, concise information about the API's functionality and requirements, making it easier to integrate with other systems and components.
7. Enhanced scalability: By thoroughly testing the API's performance characteristics, developers can ensure that the API will scale correctly and handle the expected load, improving the end-user experience.
8. Better documentation: API testing also helps to ensure that the API documentation is complete, accurate, and up-to-date, making it easier for other developers to use and integrate with the API.

 8.       Name some common protocols used in API testing?

Some common protocols used in API testing include:

1. HTTP(S): The Hypertext Transfer Protocol (HTTP) and its secure variant HTTPS are the most widely used protocols for communication on the internet. Many web APIs use HTTP(S) as the primary means of communication.
2. SOAP: Simple Object Access Protocol (SOAP) is a protocol for exchanging structured data in the implementation of web services in computer networks. It uses XML as its message format, and can be carried over a variety of lower-level protocols, including HTTP and SMTP.
3. REST: Representational State Transfer (REST) is an architectural style for building web services. It is based on a set of constraints and principles, and emphasizes the use of standard HTTP methods (such as GET, POST, PUT, and DELETE) to perform operations on resources.
4. gRPC: gRPC is a high-performance, open-source framework for building remote procedure call (RPC) APIs. It uses the Protocol Buffer data serialization format and the gRPC protocol to create high-performance, highly-scalable APIs.
5. GraphQL: GraphQL is a query language and runtime for building APIs. It allows the client to define the structure of the data required, and the server will return exactly that.

These are some of the most common protocols used in API testing, but there are many other protocols and technologies that can be used depending on the specific requirements of the API and the use case it is intended for.

9.       What is the test environment of API?

The test environment of an API (Application Programming Interface) refers to the specific conditions and configurations under which the API is tested. This includes the hardware and software used, as well as the specific versions and configurations of the API, dependencies and other components.

A test environment can include:

1. Test servers: These are servers that are used to host the API during testing. They can be physical servers or virtual machines, and may be configured to mimic the production environment as closely as possible.
2. Test clients: These are the applications or systems that will be used to access and test the API. They may be test scripts, automated test tools, or manual test tools.
3. Test data: This is the data that is used during testing. It may be real data or synthetic data, and it may be stored in a test database or other data storage system.
4. Test cases: This is the set of tests that will be run against the API. They can be manual or automated and they are designed to test specific functionality or scenarios
5. Test tools: This is a set of software tools and frameworks that are used to test the API. Some examples include Postman, SoapUI, Jmeter and others
6. Test environment management: This is the process of setting up, configuring and maintaining the test environment.

Having a well-defined and well-configured test environment is crucial for ensuring that the API is thoroughly tested and that any bugs or issues are identified and addressed before the API is released to production.

10.   What are the common API testing types?

There are several types of API testing, some common ones include:

1. Functional Testing: This type of testing checks that the API functions as intended and meets the requirements specified in the documentation. This can include testing input validation, error handling, and the correctness of the results returned by the API.
2. Integration Testing: This type of testing checks how well the API integrates with other components or systems. This can include testing the API's ability to connect to a database, interact with other APIs, or connect to external systems.
3. Performance Testing: This type of testing checks the API's performance characteristics, such as response time, throughput, and stability under different loads and conditions.
4. Security Testing: This type of testing checks the API's security measures and validates that the API is protected against common security threats such as SQL injection, cross-site scripting, and others.
5. Penetration Testing: This type of testing simulates an attack on the API to identify vulnerabilities and security weaknesses.
6. Usability Testing: This type of testing checks the ease of use and user experience of the API to ensure that it is intuitive and easy to use for developers.
7. Compliance Testing: This type of testing checks that the API adheres to relevant industry standards, regulations and laws.

These are some of the most common types of API testing, but there are many other types of testing that can be used depending on the specific requirements of the API and the use case it is intended for.

11.   What is the procedure to perform API testing?

The procedure for performing API testing typically involves the following steps:

1. Plan the testing: This includes identifying the goals of the testing, the types of tests that will be performed, and the resources that will be needed, such as test data and test tools.
2. Prepare the test environment: This includes setting up and configuring the necessary hardware and software, such as test servers and test clients, as well as any test data that will be needed.
3. Design test cases: This includes creating a set of test cases that cover the different functionality and scenarios that the API will be used in. The test cases should be comprehensive and should include positive and negative test cases, boundary value test cases and security test cases.
4. Execute the test cases: This includes running the test cases and comparing the results against the expected outcomes.
5. Analyze the results: This includes reviewing the test results and identifying any issues or defects that were found.
6. Report and document the results: This includes documenting the test results and any issues that were found, and reporting them to the appropriate stakeholders.
7. Repeat testing: This includes repeating the testing process as necessary, either to verify that issues have been resolved or to test new features or changes to the API.
8. Maintenance: This includes maintaining the test environment and test cases, as well as updating them as necessary.

It's important to note that API testing can be done manually or automatically, automated testing can be beneficial in terms of saving time and increasing efficiency, but it has its own challenges such as maintenance and code-dependency. In any case, it's important to have a clear and well-defined testing strategy in place to ensure that the API is thoroughly tested and that any issues are identified and addressed in a timely manner.

12.   What must be checked when performing API testing?

When performing API testing, several key aspects should be checked to ensure that the API functions correctly and meets performance and security expectations. These include:

1. Functionality: The API should be tested to ensure that it functions as intended and meets the requirements specified in the documentation. This can include testing input validation, error handling, and the correctness of the results returned by the API.
2. Integration: The API should be tested to ensure that it integrates correctly with other components or systems. This can include testing the API's ability to connect to a database, interact with other APIs, or connect to external systems.
3. Performance: The API should be tested to ensure that it performs well under different loads and conditions. This can include testing response time, throughput, and stability.
4. Security: The API should be tested to ensure that it is protected against common security threats such as SQL injection, cross-site scripting, and others. This can include testing for vulnerabilities and checking that the API uses appropriate authentication and authorization mechanisms.
5. Error handling: The API should be tested to ensure that it handles errors and exceptions in a robust and predictable way. This can include testing for handling of invalid inputs, unexpected inputs, and edge cases.
6. Usability: The API should be tested to ensure that it is intuitive and easy to use for developers. This can include testing the clarity and completeness of the documentation, and the ease of integration with other systems.
7. Compliance: The API should be tested to ensure that it adheres to relevant industry standards, regulations and laws.

It's important to note that the testing process should be comprehensive and should include both positive and negative test cases, boundary value test cases and security test cases. By checking these aspects during the API testing, developers can identify and fix bugs and issues early in the development process, ensuring a higher-quality product and reducing the risk of costly and time-consuming issues later on.

13.   What is the best approach method to perform API testing?

There is no one-size-fits-all approach to performing API testing, as the best method will depend on the specific requirements of the API and the use case it is intended for. However, some common approaches include:

1. Black-box testing: This approach tests the API from the outside, without looking at the internal implementation. It focuses on testing the functionality and behavior of the API by sending various inputs and checking the outputs.
2. White-box testing: This approach tests the API from the inside, by looking at the internal implementation. It focuses on testing the internal structure and logic of the API, and can include testing individual functions or methods.
3. Grey-box testing: This approach is a combination of both black-box and white-box testing. It includes testing the functionality and behavior of the API from the outside, as well as testing the internal structure and logic of the API.
4. Bottom-up testing: This approach starts with testing the lowest level components or modules of the API and works its way up to the higher level components.
5. Top-down testing: This approach starts with testing the highest level components or modules of the API and works its way down to the lower level components.
6. Automated testing: This approach uses specialized software tools to automate the testing process. This can save time and increase efficiency, but it also requires significant effort to set up and maintain the test cases.

Ultimately, the best approach to API testing will depend on the specific requirements of the API and the use case it is intended for. It's recommended to use a combination of methods, testing the API from both the inside and outside, using both manual and automated testing, and testing the API at different levels and stages of development.

14.   What are tools could be used for API testing?

There are several tools that can be used for API testing, some popular ones include:

1. Postman: This is a popular tool for testing and documenting APIs. It allows developers to create, test and document APIs easily and quickly.
2. SoapUI: This is a powerful tool for testing SOAP and RESTful web services. It allows developers to test the functionality, security, and performance of APIs.
3. Jmeter: This is a Java-based tool that can be used for load testing, performance testing, and functional testing of APIs.
4. Katalon Studio: This is a comprehensive tool that supports both REST and SOAP web services. It provides various features such as record and playback, keyword-driven testing and cross-browser testing.
5. Postwoman: This is an open-source tool for testing APIs, it offers similar functionality to Postman and it's built with React.
6. REST-Assured: This is an open-source Java-based library that can be integrated with JUnit and TestNG to test RESTful web services.
7. cURL: This is a command-line tool for sending HTTP requests. It can be used to test the functionality of an API by sending specific requests and checking the responses.
8. WireMock: This is a tool for simulating HTTP services. It can be used to test an API by simulating the behavior of a dependent service.

These are just a few examples of the many tools that are available for API testing, and each one has its own set of features, advantages, and limitations. It's important to choose a tool that is well-suited to the specific requirements of the API and the use case it is intended for.

15.   What are differences between API Testing and UI Testing?

API Testing and UI Testing are two different types of testing that are used to test different aspects of a software application.

API Testing focuses on testing the functionality and behavior of the application programming interfaces (APIs) that connect the different parts of the application together. It is performed at the message layer, without a need of a UI. API testing checks the functionality, performance, security and reliability of the API.

UI Testing, on the other hand, focuses on testing the user interface (UI) of the application, including the buttons, forms, and other elements that the user interacts with. It checks the graphical representation of the application, it's usability and accessibility.

The main difference between the two is that API testing is focused on testing the backend functionality of the application, while UI testing is focused on testing the frontend or user interface of the application. The two types of testing are complementary and often performed together to ensure that the application is fully tested and functions correctly.

16.   What are the testing methods that come under API testing?

There are several testing methods that come under API testing, some common ones include:

1. Unit Testing: This type of testing focuses on individual units or components of the API, such as individual functions or methods. It is done during the development phase and it's done by developers.
2. Functional Testing: This type of testing checks that the API functions as intended and meets the requirements specified in the documentation. This can include testing input validation, error handling, and the correctness of the results returned by the API.
3. Integration Testing: This type of testing checks how well the API integrates with other components or systems. This can include testing the API's ability to connect to a database, interact with other APIs, or connect to external systems.
4. Performance Testing: This type of testing checks the API's performance characteristics, such as response time, throughput, and stability under different loads and conditions.
5. Security Testing: This type of testing checks the API's security measures and validates that the API is protected against common security threats such as SQL injection, cross-site scripting, and others.
6. Penetration Testing: This type of testing simulates an attack on the API to identify vulnerabilities and security weaknesses.
7. Compliance Testing: This type of testing checks that the API adheres to relevant industry standards, regulations and laws.

These are some of the most common testing methods that come under API testing, but there are many other methods and techniques that can be used depending on the specific requirements of the API and the use case it is intended for.

17.   What are common API errors that often founded?

API testing is crucial to identify and resolve errors in the early stages of development. Some common API errors that are often found include:

1. Incorrect or missing input validation: This occurs when the API does not properly validate input data, which can lead to unexpected behavior or security vulnerabilities.
2. Incorrect or missing error handling: This occurs when the API does not properly handle errors or exceptions, which can lead to unexpected behavior or crashes.
3. Incorrect or missing authentication or authorization: This occurs when the API does not properly check or enforce authentication or authorization, which can lead to security vulnerabilities.
4. Incorrect or missing data validation: This occurs when the API does not properly validate data before processing it, which can lead to unexpected behavior or data corruption.
5. Incorrect or missing data mapping: This occurs when the API does not properly map data between different formats, which can lead to unexpected behavior or data loss.
6. Incorrect or missing data transformation: This occurs when the API does not properly transform data between different representations, which can lead to unexpected behavior or data loss.
7. Incorrect or missing data encoding or decoding: This occurs when the API does not properly encode or decode data, which can lead to unexpected behavior or data loss.
8. Incorrect or missing data serialization or deserialization: This occurs when the API does not properly serialize or deserialize data, which can lead to unexpected behavior or data loss.
9. Incorrect or missing data compression or decompression: This occurs when the API does not properly compress or decompress data, which can lead to unexpected behavior or data loss.

These are just a few examples of the common API errors that are often found, but there are many other errors that can occur depending on the specific requirements of the API and the use case it is intended for. API testing is crucial to identify and resolve these errors early in the development

18.   What kinds of bugs that API testing would often find?

API testing is an important step in identifying and resolving bugs in the early stages of development. Some common bugs that API testing would often find include:

1. Functional bugs: These are bugs that occur when the API does not function as intended, such as incorrect results, unexpected behavior, or crashes.
2. Performance bugs: These are bugs that occur when the API does not perform well under different loads and conditions, such as slow response times, high memory usage, or stability issues.
3. Security bugs: These are bugs that occur when the API is not properly protected against common security threats, such as SQL injection, cross-site scripting, or other types of attacks.
4. Compliance bugs: These are bugs that occur when the API does not adhere to relevant industry standards, regulations and laws
5. Input validation bugs: These are bugs that occur when the API does not properly validate input data, which can lead to unexpected behavior or security vulnerabilities.
6. Error handling bugs: These are bugs that occur when the API does not properly handle errors or exceptions, which can lead to unexpected behavior or crashes.
7. Authentication and Authorization bugs: These are bugs that occur when the API does not properly check or enforce authentication or authorization, which can lead to security vulnerabilities.
8. Data handling bugs: These are bugs that occur when the API does not properly handle data, such as incorrect data validation, mapping, transformation, serialization, or compression.

These are just a few examples of the common bugs that API testing would often find, but there are many other bugs that can occur depending on the specific requirements of the API and the use case it is intended for. API testing is crucial to identify and resolve these bugs early in the development process, ensuring a higher-quality product and reducing the risk of costly and time-consuming issues later on.

19.   What is API documentation?

API documentation is a set of information that provides technical details about an API, including how to use it, how to get started, and what the API is capable of. API documentation typically includes information on the following:

1. Endpoints: The specific URLs or addresses that the API can be accessed from.
2. Methods: The different types of requests that can be made to the API, such as GET, POST, PUT, and DELETE.
3. Request and response formats: Information on the format of the data that is sent to the API and the format of the data that is received from the API, such as JSON or XML.
4. Authentication and Authorization: Information on the authentication and authorization methods used by the API, such as OAuth, API keys, or tokens.
5. Error codes: Information on the different error codes that may be returned by the API and the meaning of each code.
6. Examples: Sample code and usage examples that demonstrate how to use the API to perform specific tasks.
7. Limitations and usage policies: Information on any limitations or usage policies that apply to the API, such as rate limits or usage quotas.

API documentation is essential for developers as they need to know how to interact with the API, what the API can do, and how to handle any errors that may occur. It's also important for the API providers as it allows them to communicate the capabilities of their API and attract more users.

20.   What are API documentation templates that are commonly used?

API documentation templates are pre-designed structures that provide a consistent format for creating API documentation. There are several API documentation templates that are commonly used, including:

1. OpenAPI (formerly known as Swagger): This template is a widely adopted standard for creating API documentation. It uses a simple, human-readable YAML or JSON format to describe the API, and it can be automatically generated from code.
2. RAML (RESTful API Modeling Language): This template is similar to OpenAPI, but it uses a YAML-based format to describe the API. It is intended to be more human-readable than OpenAPI.
3. API Blueprint: This template uses a simple, markdown-based format to describe the API. It is intended to be easy to read and write, and it can be rendered as HTML.
4. Postman: This platform offers a template for API documentation, it's integrated with the tool, and it allows to generate documentation from the collections and environments.
5. ReadMe.io: This platform offers a template for API documentation, it's designed to make it easy to write and organize API documentation, and it allows to include interactive examples, code snippets, and other features.

These are some examples of API documentation templates that are commonly used, but there are other templates and platforms that can be used depending on the specific requirements of the API and the use case it is intended for. It's important to choose a template that is well-suited to the specific requirements of the API and the use case it is intended for, it should be easy to understand, and provide all the necessary information for the developer to use the API.

 

 

 

21.   When writing API document, what must be considered?

When writing API documentation, there are several key aspects that should be considered in order to make it clear, comprehensive, and easy to use. These include:

1. Audience: The documentation should be written with the target audience in mind, and should be written in a way that is easy for them to understand. It's important to consider their level of technical expertise and familiarity with the specific technologies used in the API.
2. Clarity: The documentation should be written in a clear and concise manner, using simple language and avoiding technical jargon. It should also be well-organized, with a logical structure and clear headings and subheadings.
3. Examples: The documentation should include examples of how to use the API, including sample code and usage scenarios. These examples should be clear, concise, and easy to understand.
4. Error handling: The documentation should include information on how to handle errors that may occur when using the API, including a list of error codes and their meanings.
5. Authentication and Authorization: The documentation should include information on the authentication and authorization methods used by the API, such as OAuth, API keys, or tokens.
6. Endpoints and Methods: The documentation should include information on the specific URLs or addresses that the API can be accessed from, and the different types of requests that can be made to the API, such as GET, POST, PUT, and DELETE.
7. Request and response formats: The documentation should include information on the format of the data that is sent to the API and the format of the data that is received from the API, such as JSON or XML.
8. Limitations and usage policies: The documentation should include information on any limitations or usage policies that apply to the API, such as rate limits or usage quotas.
9. Contact information: The documentation should include a way for developers to contact the API provider in case they have any questions or issues.

By considering these aspects when writing API documentation, developers can create documentation that is clear, comprehensive, and easy to use, which will help to attract more users and increase the adoption of the API.

22.   How often are the APIs changed and, more importantly, deprecated?

The frequency at which APIs are changed and deprecated can vary greatly depending on the specific API and the organization that maintains it. Some APIs may be updated frequently, with new features and functionality added regularly, while others may remain unchanged for long periods of time.

In some cases, APIs may be deprecated, meaning that the API is no longer being actively maintained or supported, and will eventually be shut down. This could happen for a variety of reasons, such as the API being replaced by a newer version, the organization no longer having a need for the API, or the API no longer being in compliance with industry standards.

It's important for the API providers to communicate the changes and deprecation plans to the developers, so they can plan accordingly. The providers should also give enough notice before deprecating an API, so that developers have enough time to transition to a new version or alternative.

It's also important for the developers to keep track of the changes and deprecation plans of the APIs they are using and make sure to update their code and applications accordingly. This can be done by regularly checking the API documentation and monitoring the API provider's website and social media accounts.

23.   What is REST?

REST (Representational State Transfer) is an architectural style for building web services. It is based on a set of principles that define how web services should be designed, including the use of HTTP methods, the format of the request and response, and the use of URIs to identify resources.

RESTful web services are based on the REST architecture and use HTTP methods (such as GET, POST, PUT, and DELETE) to interact with resources. Each resource is identified by a unique URI, and the format of the request and response is typically JSON or XML.

One of the key principles of REST is that it is stateless, meaning that each request from the client to the server must contain all the information necessary to understand and process the request. This allows for greater scalability and flexibility, as the server does not need to maintain state information between requests.

REST is widely adopted in the industry, and it's a popular choice for building web services because it is simple, flexible, and easy to implement. Many popular web services and APIs, such as Twitter, Facebook, and GitHub, are based on the REST architecture.

24.   What are Restful Web Services?

RESTful web services are web services that are built using the REST (Representational State Transfer) architectural style. These services use HTTP methods, such as GET, POST, PUT, and DELETE, to interact with resources, and they use URIs to identify resources.

RESTful web services are stateless, meaning that each request from the client to the server must contain all the information necessary to understand and process the request. This allows for greater scalability and flexibility, as the server does not need to maintain state information between requests.

RESTful web services are designed to be lightweight, simple, and easy to use. They use standard HTTP methods and can be easily consumed by a wide variety of clients, including web browsers, mobile devices, and other servers.

RESTful web services can return data in different formats such as XML and JSON, this allows the API to be easily consumed by different types of applications, whether it's a website, mobile application or any other type of client.

RESTful web services are widely adopted in the industry, and they are a popular choice for building web services because they are simple, flexible, and easy to implement. Many popular web services and APIs, such as Twitter, Facebook, and GitHub, are based on the REST architecture.

25.   What is a “Resource” in REST?

In REST, a resource is a specific item or collection of items that can be accessed and manipulated using standard HTTP methods. A resource can be thought of as a representation of a specific piece of data or functionality in an application, such as a user, a product, or a set of data.

A resource is identified by a unique URI (Uniform Resource Identifier), and it can be accessed and manipulated using standard HTTP methods like GET, POST, PUT and DELETE. For example, a resource that represents a user account can be accessed using a URI such as /users/1234, and can be manipulated using the HTTP methods like GET to retrieve user information or DELETE to delete the user account.

A resource can also have multiple representations, such as different formats or views of the same data. For example, a resource that represents a user account can be represented in XML, JSON or even HTML. This allows a RESTful service to be consumed by a wide range of clients and platforms.

In REST, the resources are the fundamental building block of the architecture, resources are the objects that are being transferred over the network. The main goal of a RESTful service is to allow the client to access, manipulate and create resources through a simple, standard and consistent interface.

1.      What type of errors we would get while testing APIs with post man , Can you please explain with an example each ?

When testing APIs with Postman, some common types of errors that you may encounter include:

1. Connection Errors: These occur when Postman is unable to establish a connection with the API server. This can happen due to a variety of reasons such as network issues, server downtime, or incorrect server configuration. An example of this error is "Could not get any response".
2. Authentication Errors: These occur when the API server requires authentication, and Postman is unable to provide valid authentication credentials. This error can occur due to incorrect username and password, expired tokens, or incorrect API key. An example of this error is "401 Unauthorized".
3. Validation Errors: These occur when the API server receives a request that does not conform to the expected format or data type. This error can occur when a required parameter is missing, the input data is in the wrong format, or the input data is outside the acceptable range. An example of this error is "422 Unprocessable Entity".
4. Server Errors: These occur when the API server encounters an error while processing the request. This error can occur due to a variety of reasons such as database errors, server-side code errors, or network issues. An example of this error is "500 Internal Server Error".
5. Rate Limit Errors: These occur when the API server limits the number of requests that can be made within a certain time frame. This error can occur when the user exceeds the allowed number of requests within the time frame or the user is not authorized to make requests. An example of this error is "429 Too Many Requests".

It is important to note that the specific error messages and codes may vary depending on the API being tested.

2.      How to create a token in API using Postman for testing ?

To create a token in API using Postman for testing, you can follow these general steps:

1. Open Postman and create a new request.
2. Set the request method to "POST".
3. Enter the API endpoint that is used for token generation.
4. Select the "Body" tab in the request builder and choose the "raw" option.
5. Enter the necessary data required to generate a token in the request body in the format required by the API, which could be in JSON, XML or any other format specified by the API.
6. If the API requires authentication, add the required authentication credentials to the request header.
7. Send the request to the API server by clicking the "Send" button.
8. If the request is successful, the API server will generate a token and return it in the response body or header.
9. Copy the token from the response and use it in subsequent requests that require authentication.

It's important to note that the specific steps for generating a token using Postman may vary depending on the API being used. You should refer to the API documentation to learn how to generate a token using Postman for that specific API.

3.      What is the use of collection in API testing using Postman ?

In API testing using Postman, a collection is a container that allows you to organize and group related requests and tests. It is a way of managing and maintaining multiple requests in a single place, making it easier to organize and execute API test cases.

A collection in Postman typically consists of a group of API requests that are logically related, and it may include test scripts, pre-request scripts, and environment variables. You can use collections to test a complete set of API functionality or to test a specific functionality of an API.

The benefits of using collections in API testing using Postman include:

1. Organizing requests: Collections help to organize multiple requests into a single location, making it easy to manage and execute them.
2. Sharing requests: Collections can be exported and shared with other team members or collaborators, making it easy to share test cases and collaborate on API testing.
3. Automating tests: Collections can be used to automate API tests by running multiple tests in a sequence or in parallel. This makes it easy to run a complete suite of API tests as part of a continuous integration (CI) or continuous delivery (CD) pipeline.
4. Centralized management: Collections allow for the centralization of API tests, which can help to avoid duplication of effort and ensure that all tests are stored in a single location.

Overall, using collections in API testing using Postman can help to streamline testing and make it more efficient and effective.

4.      How do you validate the response data against the application using Postman ?

Validating the response data against the application using Postman involves comparing the data returned by the API to the expected data that the application should return. Here are the general steps you can follow to validate the response data using Postman:

1. Send a request to the API endpoint that returns the data you want to validate.
2. Once you receive the response, open the "Tests" tab in the Postman request builder.
3. Write a test script to validate the response data. In the test script, you can use JavaScript to check the expected values in the response body, headers, or cookies, and compare them to the values returned by the API. For example, you can use the "pm.expect" function to assert the values in the response body.
4. Run the test script by clicking the "Send" button. The test results will be displayed in the "Test Results" tab.
5. If any of the tests fail, review the error message, and modify the test script as needed to correct the issues.
6. Save the test script as part of the Postman collection for future use.

It's important to note that the specific steps for validating response data using Postman may vary depending on the API being tested. You should refer to the API documentation to learn how to validate the response data using Postman for that specific API. Additionally, Postman provides built-in assertion libraries to help with validating the response data

5.      What are the different types of methods , please explain with an example for each ?

In HTTP protocol, there are several methods that can be used to interact with a resource or service. Here are the most used HTTP methods in Postman with an example for each:

1. GET: This method is used to retrieve data from a server or resource. It is used to read data from a specified resource.

Example: To retrieve a list of all users in a system, you would use the following GET request URL: https://api.example.com/users

2. POST: This method is used to submit an entity to the specified resource, often causing a change in the server's state. It is used to create a new resource or update an existing one.

Example: To create a new user in a system, you would use the following POST request URL: https://api.example.com/users and include the user details in the request body.

3. PUT: This method is used to update or replace an existing resource with new data. It replaces all current representations of the target resource with the request payload.

Example: To update a user's information in a system, you would use the following PUT request URL: https://api.example.com/users/123 and include the updated user details in the request body.

4. PATCH: This method is used to update or modify an existing resource with new data. Unlike PUT, it only applies a partial update to the resource.

Example: To modify a user's information in a system, you would use the following PATCH request URL: https://api.example.com/users/123 and include the updated user details in the request body.

5. DELETE: This method is used to delete a specified resource.

Example: To delete a user from a system, you would use the following DELETE request URL: https://api.example.com/users/123

6. OPTIONS: This method is used to describe the communication options for a resource or server.

Example: To retrieve the allowed methods for a resource, you would use the following OPTIONS request URL: https://api.example.com/users/123

These are the most commonly used HTTP methods in Postman for API testing, and there are other less commonly used methods as well.

6.      Define the process and code for API testing using rest assured with Java and BDD for posting a request using post and an assertion to validate the response

Sure, here's an example of how to use RestAssured and BDD-style syntax in Java to test an API endpoint by sending a POST request and validating the response:

import io.restassured.RestAssured;

import io.restassured.http.ContentType;

import io.restassured.response.Response;

import org.junit.Assert;

import org.junit.Test;

import static io.restassured.RestAssured.*;

import static org.hamcrest.Matchers.*;

 

public class PostRequestTest {

 

    @Test

    public void testPostRequest() {

 

        // Set the base URI for the API endpoint

        RestAssured.baseURI = "https://your-api-endpoint.com";

 

        // Define the request body as a JSON object

        String requestBody = "{ \"name\": \"John Doe\", \"email\": \"johndoe@example.com\" }";

 

        // Send the POST request and store the response

        Response response = given()

                .contentType(ContentType.JSON)

                .body(requestBody)

                .when()

                .post("/api/users");

 

        // Assert the status code of the response

        response.then().statusCode(200);

 

        // Assert the response body

        response.then()

                .body("name", equalTo("John Doe"))

                .body("email", equalTo("johndoe@example.com"));

    }

}

 Here's a breakdown of what's happening in this code:

·         We set the base URI for the API endpoint using RestAssured.baseURI.

·         We define the request body as a JSON object and store it in a String variable.

·         We send the POST request using given().contentType(ContentType.JSON).body(requestBody).when().post("/api/users"). This sets the content type to JSON, sets the request body, and specifies the endpoint to send the request to.

·         We store the response in a Response object.

·         We use response.then().statusCode(200) to assert that the status code of the response is 200 (OK).

·         We use response.then().body(...) to assert the response body. In this example, we're checking that the "name" field is equal to "John Doe" and the "email" field is equal to "johndoe@example.com".

This is just a basic example, but you can customize it to fit your specific API endpoint and testing needs.

 

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