Testing teams face several unique challenges when testing Application Programming Interface (API) implementations. API testing is part of the integrations testing process and concerns the communication between two systems–one of which your staff likely has no control over.

Thorough testing practices help QA and development teams not only create code that works, but create code that works efficiently. The following six challenges are particularly important when testing APIs:

1. Initial Setup of API Testing

Manual testing helps confirm whether something works. Automated testing is necessary with APIs to gauge how well they perform under pressure. Getting the testing infrastructure up and running is often one of the most challenging parts of the process–not because it is particularly difficult, but because it can be a substantial motivation-killer. Once you manage to motivate your team to get through the process, however, it pays off over the long-term.

2. Updating the Schema of API Testing

The schema–in other words, the data formatting that handles requests and responses for the API–needs to be maintained throughout the testing process. Any updates to the program that create additional parameters for the API calls need to be reflected in the schema configuration.

3. Testing Parameter Combinations

APIs handle communication between systems by assigning data values to parameters and passing those parameters through data requests. It’s necessary to test all possible parameter request combinations in the API to test for problems pertaining to specific configurations. A larger project could end up assigning two different values to the same parameter, or create instances where numerical values appear when text values should be. Adding an additional parameter exponentially increases the number of possible combinations.

4. Sequencing the API Calls

In many cases, API calls need to appear in a specific order to work correctly. This creates a sequencing challenge for the testing team. For example, if a call to return a user’s profile information goes through before the profile is created, the request will return an error. Alternatively, a call to create a map needs to run prior to placing location pins on the map to work correctly. This process can get increasingly difficult when working with multiple-threaded applications.

5. Validating Parameters

Testing teams may find validating the parameters sent through API requests challenging as well. The sheer number of parameters and use cases for those parameters can make it a daunting task. The team needs to make sure all parameter data uses the correct string or numerical data type, fits within length restrictions, fits within a designated value range, and passes other validation criteria. For example, U.S. phone numbers should appear in a 10-digit format, and returning a 5-digit zip code should trigger an invalidation error.

6. Tracking System Integration

The final challenge is making sure the API testing system is working correctly with the data tracking system. This is necessary to bring back correct responses on whether a call is working correctly. It’s also used to passively monitor API performance. Since this step can come late in the process, the team may be too fatigued to give it the attention it needs.

API testing is an essential part of application development in the modern business environment. If your company is looking for the tools and expertise to thrive with API implementation, contact the experts at Apica today.