September 10, 2020
API, Application Programming Interfaces is the set of protocols, functions, commands, and objects utilized by programmers to interact with external environments and systems. It takes care of the need to do repetitive backend coding repeatedly. It reduces the need to do multi-platform coding for different environments.
It is a type of testing, also referred as Web Services Testing that validates APIs. Software or tools are generally used to send calls to the server through API and output is analyzed based on the way the system responds.
It is crucial when testing any application to ensure:
The API executes the business logic. The classes, functions, and procedures making up the API form the business logic layer of the application. This needs to be tested properly failing which the API can malfunction when calling the application.
Unlike GUI tests, API tests do not focus on the appearance of the application but more on the functionality of the features. API tests must ensure that business logic works accurately.
Prior to testing, it is important to thoroughly gather the API’s requirements. How the API is placed in the larger application workflow and its functions will allow you to test input and output data while setting the method of verification whether it is API to API comparison or verification against the database.
API testing should cover at least following testing methods apart from usual SDLC process:
API discovery is a crucial part of API integration and performance. API discovery is all about gathering the minutest of details that enable flawless functioning of the API. API discovery primarily deals with detailing documentation that decides the road-map to API testing.
Often, many applications, software or websites operate on multiple APIs leading to noise, a situation that API discovery will help mitigate and minimize.
In the discovery phase, API calls documented from R&D and client specifications must be manually executed for further verification. This is what prompts the QA team to ensure high performance of the API.
APIs often fall prey to hacker attacks. That is why it is vital to perform API security testing to address all the possible loopholes which can be exploited by an attacker.
Any developer team or user relying on your API can fall prey to cyber attacks if your API has not passed the ‘security testing’ benchmarks. Security testing for API primarily includes testing the need for authentication and data encryption over HTTP.
API testing with the widest coverage can be possible when using Automated testing. API testing is based on a set flow of processes:
Data Input ---> Data Output ---> Outcome Validation and Verification
Carrying out these individual tasks is a breeze when compared to managing the amount of test data generated which then needs to be further verified. Test data verification methods can often be tricky and can make or mar the entire testing exercise for the API and the application. This is where test automation for API testing comes in handy.
Best practices dictate that an API prototype must be developed early on so functionality based on the business logic can be frozen. Functional testing can then be performed in detail on this prototype. This sets the functional flow of the API so when the API is actually tested as a part of the final product, the ROI of the project automatically increases since more than half the work of the Quality Assurance team is already done. In addition, it increases the test coverage.
Below are some major bugs and defects one can expect to unearth from API testing:
A codeless test automation tool like TestingWhiz can make API testing hassle free without the need to write extensive automation scripts. Before selecting the right tool to automate your API testing, you need to ensure the tool supports REST and SOAP services with a series of standard authorization methods since API cannot function without authorization. Any test automation tool you select must offer the capability of helping you carry out a variety of other tests including web test automation, mobile testing, cross browser testing and more.