Application programming interface (API) test automation is a critical part of ensuring the reliability and performance of APIs. While manual testing is possible, automated testing can be more efficient and accurate, and any tool that facilitates automated API testing can make it a wise choice.
While you can always write your own code for API test automation, several vendors offer platforms that bootstrap individual coding efforts and allow testers to create automated tests with a minimum of scripting. This means that you will have more time to think about what you are actually testing instead of writing code from scratch. And the easier it is to learn the tool, the better.
Developing Comparison And Evaluation Criteria
When selecting an API test creation tool, it's crucial to compare and evaluate the available options based on various criteria. Each criterion plays a significant role in determining how well a tool aligns with the specific testing needs and requirements of a project.
Let's delve deeper into an example set of comparison and evaluation criteria for popular API test creation tools.
Ease of Learning and Use
- Assess the tool's user interface and overall user experience. Is it intuitive and easy to navigate?
- Consider the learning curve for testers who are new to API testing or have limited coding experience.
- Determine the availability of resources such as documentation, tutorials, and community support to aid in learning.
Versatility and Coverage of API Types Supported
- Evaluate whether the tool can handle different types of APIs, including RESTful, SOAP, GraphQL, and so on.
- Check if the tool supports testing APIs with various authentication methods, such as OAuth, API keys, or JWT tokens.
- Consider the tool's ability to test APIs that use different data formats like JSON, XML, or form-urlencoded data.
Level of Coding Required
- Examine the tool's approach to test case creation — GUI-based or code-based.
- Determine the extent to which testers need to write code for creating and managing test cases.
- Consider whether the tool allows testers with limited coding skills to perform essential testing tasks.
Test Script Creation Options (GUI-based or code-based)
- Compare the advantages and limitations of GUI-based test creation.
- Assess the flexibility and control provided by code-based test script creation.
- Consider which approach aligns better with the testers' skillset and the project's testing requirements.
Integration Capabilities with Other Tools and Frameworks
- Check if the tool can seamlessly integrate with popular continuous integration / continuous delivery (CI/CD) tools like Jenkins, GitLab, or Travis CI.
- Assess the tool's compatibility with version control systems and issue-tracking tools.
- Consider integration with performance testing tools, if performance testing is a requirement.
Documentation Generation and Reporting Features
- Evaluate the tool's ability to generate API documentation automatically from test cases.
- Check if the tool provides comprehensive and customizable test reports for analysis and tracking.
- Consider whether the tool can generate reports in various formats, such as HTML, PDF, or CSV.
Collaboration and Team Management Capabilities
- Examine the tool's collaboration features, such as sharing test cases and test data among team members.
- Check if the tool offers role-based access control to manage permissions for different team members.
- Consider cloud-based features for seamless collaboration among distributed teams.
Comparing Some Popular API Test Creation Tools
Postman
Postman stands out as one of the most popular and user-friendly tools for API testing. Its graphical user interface (GUI) makes it an excellent choice for testers new to API testing or those who prefer a no-code approach.
However, to automate API testing fully using Postman, you'll need to invest time in writing scripts to handle various scenarios, data manipulation, and response validation. Without leveraging these scripting capabilities, Postman might function more as a manual testing tool.
Key features of Postman include:
- GUI-based test creation: Testers can effortlessly create, manage, and execute API requests without writing any code, simplifying the testing process.
- Scripting with JavaScript: While no coding is required for basic tests, testers can enhance their tests by using JavaScript for more advanced scenarios.
- Import and export: Postman allows you to import and export API collections and environments, making test management more convenient.
- Documentation generation: Testers can easily generate API documentation within the tool.
- Integration and collaboration: Postman integrates seamlessly with popular tools like Jenkins, GitLab, and Swagger, streamlining the testing process. Additionally, testers can collaborate efficiently using Postman cloud services.
SoapUI
SoapUI is a powerful API testing tool with extensive capabilities, making it suitable for complex testing scenarios. It provides both a free version with limited features and a paid version, known as ReadyAPI, with advanced functionality.
While SoapUI may require a bit more effort to learn compared to Postman, it is still a viable option for testers who prefer a GUI-based approach. Also, just like Postman, to automate API testing in SoapUI, scripting is often required. SoapUI uses Groovy scripting, a powerful and dynamic programming language that's particularly well-suited for testing and automation.
Key features of SoapUI include:
- SOAP and REST support: SoapUI supports testing both SOAP and REST APIs, making it versatile for different API types.
- Functional and performance testing: Testers can perform functional, performance, security, and load tests with SoapUI, ensuring comprehensive testing.
- Scripting with Groovy: SoapUI allows testers to write custom scripts using the Groovy scripting language, providing greater flexibility in testing.
- Integration and collaboration: SoapUI can integrate with tools such as Maven, TestNG, JUnit, and Jenkins, offering better collaboration options through its cloud services.
Rest Assured
Unlike Postman and SoapUI, Rest Assured is a Java-based library, not a standalone tool. This library allows testers to conduct API testing by adding it as a dependency to a Java project using Maven or Gradle. While Rest Assured is a code-based approach, it may be the easiest to learn for testers proficient in Java.
Key features of Rest Assured include:
- Fluent and expressive syntax: Testers can write expressive test cases in Java using a given-when-then syntax, making the tests more readable and maintainable.
- Support for JSON and XML responses: Rest Assured can test both JSON and XML responses, catering to different API formats.
- Response validation: The library enables validation of response status, headers, body, and schema, ensuring thorough testing.
- Integration with libraries: Rest Assured integrates well with other libraries such as TestNG, JUnit, Hamcrest, and JsonPath, enhancing the testing capabilities.
Choosing One Of The Popular Tools On Short Notice
Based on the comparison and evaluation criteria discussed above, consider the following guidelines to select the best API testing tool for your needs:
- Postman is an excellent option if you are new to API testing or prefer a GUI-based approach.
- SoapUI or ReadyAPI may suit your needs if you have some coding skills and require a more comprehensive tool.
- Rest Assured is a good option if you are proficient in Java or prefer a code-based approach.
Ultimately, the choice depends on your specific project requirements, API complexity, and the level of coding skills within your team.
Conclusion
API test automation is an essential part of modern software development, and you should select the tool most appropriate for your testers and development environment. Postman, SoapUI, and Rest Assured are some of the most popular API test creation tools, each with its own set of features and benefits.
Testers should consider their experience, project requirements, and coding preferences when choosing the most appropriate tool for their API testing needs. By exploring and experimenting with these tools, testers can make an informed decision and improve the quality and reliability of their APIs.
For More Information
- Systematic Exploratory Testing With YATTIE, by Rahul Parwal
How to Misuse 'Automation' for Testing, Fun and Productivity, by Alan Richardson
