API testing involves testing application programming directly and integration testing to determine if they are up to standard in functionality, reliability, performance, and security.
APIs lack a GUI, and therefore API testing is conducted at a message layer. API testing can either be manual, where you create your code to test the API, or automatic, using testing tools like SoapUI.
This article talks about the top practices for API testing.
This is a significant step where you must write clear tests that allow debugging. When tests are running successfully, they rarely do require time or attention. However, when the same resources are faulty, you need to allocate resources to find the origin of the failure.
You might not want to undergo this process when developing a new product. The process might push deadlines or even cut on new lucrative features from your product.
Some of the reasons your tests fail are flaws and instability in automated testing, environmental failure or limitation, and changing the product but failing to change the testing. You can try debugging if you want to save resources and optimize the process when you create a test.
You have to test each system separately for each configuration, and you can also include additional information like descriptors to make the report more informative.
2. Do Not Repeat Yourself
You have to create a client for your system under test before adding any tests. Programming is very sensitive, and as such, you should avoid repeating the code even though many tests recommend that you address the same components.
If you need to address similar actions, you can consider creating a standard library to wrap the test requests. The library also makes the process simpler and its usage shorter.
3. Take Care of Other Factors
It would help if you had the parameters for your test. You can list all mandatory and required parameters in a JSON request. During performance testing, check the number of concurrent connections a server can hold before it faults.
You have to check the expected response and queries undergone per second. API automation tools are essential as they require less code and thus provide faster test results.
API performance functionality is integral, and you have to keep tabs on it using API tests. These tests are important to recognize availability and speed issues. After several tests, you can use the data you collect to analyze performance trends.
Furthermore, API testing involves data exchanges, so it is necessary to ensure that the data is reliable since you will need to test more than just the API`s availability.
To test if the APIs are functioning as required, you can validate the inputs and ensure you have structured the data well. It is vital to measure the impact on the existing API integrations when creating new features to recognize issues before the real-time users are affected. You can also test all the application API dependencies to ensure you do not degrade performance.
5. Treat The API You Are Testing Like a Consumer Would
Remember that you are creating an API for consumer consumption. You have to view yourself as a consumer and try to make the errors that a consumer would make knowingly or unknowingly.
It would be best if you did not put all your focus on what you think is the proper response. Rarely do things break in a typical environment? It would be rational to test like you are already there in such a situation.
6. Eliminate Unnecessary Fixed Data Sources
API endpoints often rely on the output from other APIs when in a live environment. To ensure that the process moves on as it should create an integration test that calls the first API and then uses the result of that call to hit the second. The key principle here is to create integration tests instead of testing individual endpoints solely.
7. Structuring Testing
An API integrates various methods and operations you can test individually or through a scenario setup. To test any API, perform syntax testing of individual methods and operations where possible. Syntax testing determines if ignoring essential fields can bring an error and if the API accepts optional fields as readily as expected.
8. API Virtualization
Virtualization of an API can be required in specific scenarios like when you have not yet developed the component, If the component holds insufficient data and if the component is shared with other teams and thus it does not have free usage.
Finally, if you want to test applications in an agile environment, consider the above steps as they are among the best automation practices. API testing is critical to ensure that your API works as it should.