API testing is kind of software testing that makes first-hand use of testing application programming interfaces (APIs) and as part of integration testing in order to comprehend if they live up to expectations for functionality, efficiency, trustworthiness, and security.
As APIs have become rather more prevalent in contemporary software development, testing and ratifying these APIs has become increasingly significant to guarantee the quality of your software.
There are so many perks associated with API Testing. The most prominent is that they enable you to test end-to-end behavior conveniently while not being bothered to invest in writing and maintaining UI-based testing by imitating the API calls clients would produce.
This allows for a firm and easy-to-write tests and can also recognize exactly where your system issues arise. API tests can also be conveniently run as monitors, helping you to conveniently identify outages and efficiency degradations prior to your users.
Let’s have a look at some of the important tips that can help you in better understanding of API Testing.
1. Understand the API Behavior Better
The foremost step for writing any kind of API tests is to successfully develop a better understanding of what the API does and how it works. There are basically three levels of comprehending what the API does, i.e. API Scope, Endpoint Functionality and User Flows.
As far as API Scope is concerned, it comprehends as to what functionality does this API offer, and it often takes the form of merely comprehending what endpoints the API offers (for RESTful APIs) or what modifications and queries the API exposes (for GraphQL APIs).
When it comes to an understanding the Endpoint Functionality, we should start developing a close understanding of these endpoints and the parameters they expect. Besides, you should also understand the range of possible values, the edge cases and the outcome of their occurrence. One of the fascinating ways to do this is by requesting each endpoint while trying various scenarios and inputs till you understand you have a firm grasp of how it works.
The most important level in understanding the API Behavior is to comprehend User Flows as it helps us in learning how APIs come together in an application. Try to take a comprehensive look at the application consuming these APIs and ensure that you have better understood the app usage and its API leverage.
Truth be told, you can write better tests if you spend more time in comprehending the API in real sense.
2. Set the Output of the API Tests
As far as the output of the API tests is concerned, it can vary from pass/fail status to any sort of relevant or invalid data or a call to other API. It is also worth mentioning that you should not skip the fact that there can be times when there will be no outputs in various tests. Moreover, it can also be tricky and even risky, to measure the outcomes of the tests with the desired results.
Try to ask yourself certain question while setting the output of the API Tests.
Do you find specifying the output to be rather challenging?
What should be done in understanding the pass/fail scenarios?
What should be done in case if output comes out of the ordinary while we compare the API tests with either their responses or the behavior? Make sure that your team is always prepared for certain unpredictable outputs, and that is why data-driven API testing is the type you need to commence.
3. Focus on Small API Functions
While performing API Testing, you should keep in mind that it is not a type of testing where you can directly jump on writing huge test cases. Comparatively, developing small API test cases is not that bothering as you can easily write small API test code and test regardless of the fact as to whether the output is expected or not.
Comparatively, clubbing or adding dependencies of several tiny successful API functions would rather be an efficient and time-saving exercise. It is worth mentioning that while we perform API testing using SOAP (Simple Object Access Protocol) or REST (REpresentational State Transfer), we write two completely different test cases for two separate functions, like user authenticity and password reset. Through this way, we can easily impose reliance on the second on the first test case.
4. Ensure the Introduction of Automated Testing
While keeping in view the fact that writing codes for API Tests can be annoying, it’s time to get over manual testing and move on towards automated form. Gone are the days when testers would write complicated codes to test the code.
Unlike the previous days, when the majority of the enterprises did not that much accept it, the situation is now clear when it comes to introducing an automotive form of testing to their routine software testing activities.
5. Try to Impose Usability Testing
It is also rather tricky to impose usability testing in APIs. From what we know about API, they apparently look like a kind of a black box to the user, and that is why it is difficult to debug them.
The simple example can be the testing of the application’s user authenticity. In this case, we check as to whether we are gained access to log in or not when we feed an incorrect password.
For this purpose, we will try to write a negative API test case, and for that, we will feed the wrong password and check as to whether we receive response “Access Denied.”
This aforementioned negative API code can help us in finding the errors more conveniently rather than comparing to receive no output or rather an uncertain output.
While keeping in view the fact that API testing is quite significant and its demand increasing day by day, a complete understanding of API testing along with good API automation testing tools will definitely help us in deploying more secure and quality applications on time. The tips mentioned above would rather help more towards the cause.