API Testing for Reaching Quality and Coverage Goals

For APIs to perform reliably including addressing security concerns, we present five top test practices.

1) Test a wide span of corner cases and conditions and use automated validation extensively.

A high level of automation provides an array of functional test scenarios which you can replicate systematically.

Use an intuitive interface to automate complicated cases over databases, microservices, the messaging layer, etc. This includes:

• Specifying automated test cases along a wide range of test types and protocols that developers use for APIs like HTTP/REST, Swagger, Kafka, MQ, JSON, EDI, JMS, and fixed-length messages.
• Parameterization of validations, test loads, and configurations from test cases, data sources, or variables.
• Definition of high-level test logic but without scripting.
• Visualization of how events and messages move through architectures while tests execute.
• Automation of full omnichannel validation along numerous endpoints and interfaces included in end-to-end test cases.

2) APIs continually change, which presents risks in security and quality for companies that don’t keep up.

Therefore, it’s essential to recognize when API changes occur and easily, quickly, and accurately update test assets to align.

The key is to develop a system that assesses changes needed for current tests and then updates them or even creates new tests. This can substantially reduce the time and effort it takes to be sure that your tests do not fail as a result of unexpected changes and that they don’t ignore new functionalities.

3) Use service virtualization for simulated test scenarios.

This allows you to create simulated test cases, which in turn allows you to view behaviors of dependent resources that you may have a hard time accessing, that you may have difficulty configuring for testing, or that are not yet available.

These resources might be web services, databases, mainframes, or third-party applications, among others. You can use web service virtualization together with OS and hardware virtualization to gain access to the required environments. Combined, this allows you to test faster, earlier, and more thoroughly.

You can apply service virtualization in two ways with regard to API testing:

• Simulate access to the behavior of the dependent resource, such as a database, a mobile app, a third-party service, or a legacy system.
• Simulate your API’s behavior by developing a test scenario API users can create and test for that doesn’t affect the production product. This also allows development and subsequent testing even if APIs are not yet complete.

4) Use service virtualization for extensive performance testing.

APIs are highly exposed. Thus, a great potential for volatile and unpredictable traffic exists. It’s wise to use broad performance testing to determine if your API meets expectations when it encounters surging demand or erratic behavior. Here are some examples.

Service virtualization allows you to create simulated test scenarios that assist you in testing various performance environments that are normally problematic to create in a test situation. You can test conditions like timing, delay, and latency to replicate typical, peak, and slow performance in an effort to plan for a cloud burst or someone accessing the API from a remote location on another continent.

In addition, you can create various failure and error situations that testers often find hard to reproduce in the actual program – like if your APIs use Amazon Web Services, you can create a scenario that simulates a situation where AWS is offline.

You can also configure a wide range of situations in dependent systems in order to discover if your APIs deliver proper responses under non-ordinary conditions and also if they fail reasonably well.

You may replicate links to third-party applications, which can negate any risk your tests may have on services that you are not normally allowed to attack with test data or for which you are not budgeted.

5) Test broadly for security issues using service virtualization.

APIs unfortunately offer a large surface attack area. To help stop attackers and major security problems, use a multi-faceted test approach. This ensures that you have written the necessary measure of security into the application. The approach includes:

• Creating a wide range of penetration and attack situations that involve injections, parameter fuzzing, big payloads, and so on.
• Implementing complex encryption, authentication, and access-control testing situations.
• Running penetration attacks aimed at existing operational test situations.
• Monitoring the backend as you test to discover if security has been compromised.

As a money saver, service virtualization allows non-security experts to perform tests because they are not writing code but simply executing proven tests in a wide variety of scenarios. And service virtualization enables you to target your API’s responses to a variety of dependency security behaviors and in numerous attack situations.