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API Testing: The Application Program Interfaces (APIs) have become the center of attention for application and device integration. The APIs work as a focal point between the different devices and applications in the whole process of development, data & logic transmission, and connection. For developing a crucial software application, Application Program Inte

rface (APIs) works as a set of protocols, tools, and processes.

With the help of instruments, protocols, and code, APIs enable connectivity between system and applications and also permit the data exchange activity among them. Application Program Interface allows communication and data interchange between diverse software systems.

With the growth of agile methodology approaches for developing software and testing are advancing. Agile processes deliver great quality products while managing teamwork more efficiently and effectively even in the budget limitation. Whatever processes companies are choosing for testing their software, it always stands on the first priority list. So, it has the topmost value in the Agile world as it provides unique profits.

In this blog, we will understand some basic things about the in the Agile world:

What is API Testing ?

Role of api testing in the agile world — Image Credit: Pexels

A type of software testing that validates and performs authentication straightly at the API level. The objective of Application Programming Interface testing is to examine the utility, reliability, performance, and security of the programming interfaces.

Application Programming Interface is a linking bridge between diverse systems and different layers of applications which are Presentation Layer, Database Layer, and Business Layer.

The Application Programming Interface works in the business layer and directly reaches both the application and data layers. These layers describe the guidelines of user interaction with the data, services, and operations of the application.

API identifies several errors and bugs concentrating on functionality, operation, performance, and safety. It also finds the missed flaws of automation testing and manual testing.

It is distinct from the GUI testing as it does not focus on the look and feel or button’s functionality of an application. It mainly concentrates on the logic, performance, and security of a business.

Types of API Testing –

1. Validation Testing

Validation testing plays an important role in the development process and happens at the final step of the whole operation. This testing determines the quality of the product, their behavior, and performance.

2. Functional Testing

Functional testing includes testing of specific functions in the codebase. For the confirmation of handling within a specific system, Function testing is performed.

3. UI Testing

UI testing gives more importance to the interface which binds into the API rather than the itself. UI testing is described as a test of the user interface for the API and other connected parts. It only provides a brief of the efficiency and condition of the app’s front and back ends.

4. Security Testing

Security testing is performed to give surety of the safety of the API implementation from external risk. Security testing contains validation of encryption, methodologies, API access control and end-user rights management and authorization validation.

5. Load Testing

Load testing is executed to check the status and condition of the theoretical solutions as per the planning. Load testing controls the app’s achievement at both normal and peak conditions.

6. Runtime and Error detection Testing

Runtime and error detection testing are involved with the actual flow of the API rather than the implementation of the API to the environment. This testing focuses on one of the below feature i.e: monitoring, execution errors, resource leaks, or error detection.

Advantages of API testing above Standard UI testing:

Only through the Application Programme Interface testing, you can provide an absolutely secure, trustworthy and scalable connection between the platforms.

In Application Programme Interface (API) testing, end to end functional testing of a product or system is performed while in User Interface testing different functionalities of a product are tested.
The main advantage of Application Programming Interface testing is that it permits access to the application without having interaction with a diverse system. This supports the tester to identify and recognize the errors earlier than GUI.
Application Programming Interface it is faster and can be performed quickly compare to GUI testing.
it needs outstanding inputs and requirements, which shields the application from malicious code and damage. Application Programming Interface testing helps in removing the shortcomings.
Application Programming Interface (API) testing is very easy and simple than User Interface testing.
API testing provides faster test results with better test coverage, as API test automation needs very less code than GUI automation. The final result of faster testing gives a large reduction in overall testing costs. API testing detects the error in a small amount of time or earlier so it also decreases the manual testing cost.
Application Programming Interface (API) Testing is technology independent. So, It allows you to choose any basic language for your application while testing.

List of Tools for API testing

Listed below are some tools which are used in API testing

Runscope
Postman
Curl
Cfix
Check
CTESK
dotTEST
Eclipse SDK tool- Automated API testing
Katalon Studio
SoapUI
Parasoft
MicroFocus UFT
vREST
Jmeter

Things which verified under

Data precision
HTTP status codes.
Response time.
Error codes if API returns any errors.
Authorization checks.
Non-functional testing such as efficiency testing, safety testing.

The Approach of API Testing

Understanding the features of the API program and describe the scope of the program clearly.
Use testing methods such as boundary value analysis, and error guessing and record test cases for the API.
Input Parameters for the API should be planned and explained properly.
Do a comparison between the expected and actual results after the test execution.

Process of API Testing

Set up the environment
Describe the test plan
Do an API call
Merge data with API tests

Conclusion

Application Programming Interface Testing is work in the business layer which links the Application layer and Data layer and easily connected with both of them. API contains a set of functions, classes, and procedures which represent the business layer logic.

Testing of an API is an essential part of the application because any mistake in this step may cause an issue in both API applications and the calling application. It is a crucial test in software engineering.

API automation testing is highly recommendable and considered for a real development project and Agile world.

Ashish Mittal

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