API testing is a software testing used to directly perform verification at the API level. It is an integration testing that is used to determine if the APIs meet the expected levels of reliability, security, performance and functionality. As a beginner, you might find it a little bit difficult to understand what is required when testing APIs. In this article, we will talk about the best API testing tips to guide you when testing APIs.
Understanding the API Requirements
Before you start testing the API, you need to understand its purpose and the workflow of the application that will be using the API. Understanding the purpose of the API helps in setting a good foundation when preparing the test data for both input and output as well as defining the verification approach. This will make it easy for you throughout the testing process.
Live Testing Process
It is recommended to schedule the API test execution every day while the testing process is live. It is easy to add more tests into a testing process because API test execution is stable, fast and small. However, this is only possible with automated API testing tools. This is because these tools come with features such as;
- Test scheduling that has built-in test commands
- Integration with tracking tools and test management tools
- Generation of visual log reports
You can then get the results of completed tests everyday. In the case of failed tests, check the outputs to validate issues to get the best solutions.
Focus on Small Functional APIs
In a project, you will find some simple APIs that have a couple of inputs. A good example of such APIs may include the get token API, login API and others. However, these small APIs are important since they are the entry point to more complex APIs. When performing a test, it is important to focus on these APIs before the others to ensure that the API environment, servers and authentication work as expected. Also, avoid testing more than a single API at once. This will help in being able to identify errors when they occur.
The API Output Status
The response status code is the most common API output that needs to be verified in API testing. Most new API testers use the 200 response code to decide whether an API has passed all tests or not. Although this is not wrong, it does not show all the test scenarios of an API. API response codes are classified into five different categories with the first digit of the status code defining the class of response. Here are the first digits in the categories and there meaning;
- 1** – informational
- 2** – successful
- 3** – redirection
- 4** – client error
- 5** – server error
However, you need to verify whether the API’s code follows the global standard cases above or it is specified in the requirement.
Organizing the API Endpoints
When testing a project, you might have a few or many APIs to test. It is therefore important for you to group the APIs into categories to make sure that you have a good test management. When doing this, make sure to place APIs that share some common information such as path and resource type into the same category. This will help in creating test scenarios that have high coverage and integration. It will also help in making your tests extendable and reusable.
With these tips, you should now be ready to conduct API testing and many other software testing types without any problems. You will find the whole process quite easy and straightforward even as a beginner.
