What is API Testing?

API Testing is a software testing type that validates Application Programming Interfaces (APIs). The purpose of API Testing is to check the functionality, reliability, performance, and security of the programming interfaces. In API Testing, instead of using standard user inputs(keyboard) and outputs, you use software to send calls to the API, get output, and note down the system’s response. API tests are very different from GUI Tests and won’t concentrate on the look and feel of an application. It mainly concentrates on the business logic layer of the software architecture.

How to Test API

API automation testing should cover at least following testing methods apart from the usual SDLC process

• Discovery testing: The test group should manually execute the set of calls documented in the API like verifying that a specific resource exposed by the API can be listed, created and deleted as appropriate

• Usability testing: This testing verifies whether the API is functional and user-friendly. And does API integrates well with another platform as well

• Security testing: This testing includes what type of authentication is required and whether sensitive data is encrypted over HTTP or both

• Automated testing: API testing should culminate in the creation of a set of scripts or a tool that can be used to execute the API regularly

• Documentation: The test team has to make sure that the documentation is adequate and provides enough information to interact with the API. Documentation should be a part of the final deliverable.

Types of API Testing

• Unit Testing

While the testing world can be filled with misnomers, the easiest way to think about a "unit test" and APIs is testing a single endpoint, with a single request, looking for a single response or set of responses. Many times, this type of testing can be done manually via the command line and something like a URL command or with lightweight tools like SoapUI.

• Contract Testing

Contract testing is a technique which validates that two separate systems (such as two microservices) are able to communicate. The interactions exchanged between each service are captured and stored in a contract which is used to validate that both systems adhere to a common agreement. The simplest way to orchestrate contract testing is with Pactflow.

• Integration Testing

Integration testing is the most often used form of API testing, as APIs are at the center of most integrations between internal or third-party services.

• End-to-End Testing

End-to-end testing can help us validate the flow of data and information between a few different API connections.

Why Keploy for API Testing?

Keploy is an open-source functional test case and data mock generation platform. There are 4 Major reasons why you should use Keploy.

1. Dependency Mocking Keploy records the exact API calls, including dependencies data. So if you're still writing data mocks for any external service like Databases, third party vendors like stripe, twilio, razorpay, cloud services, etc. Keploy will automatically create mocks for these.

2. Automated Assertions Keploy automatically compares all attributes of an actual and expected test-case response and brings any differences to your attention.

3. Detailed Test Reports Keploy will test the new version of application with thousands of test cases within minutes and generate instant reports and alerts so that you don't miss on anything!

4. Simple CI/CD Integration Keploy has native integrations with native testing libraries like go-test, junit. Code coverage will be reported with existing plus Keploy recorded test cases and doesn't require any change in the CI/CD pipeline to integrate.