Prepare for API testing

Unit testing is the basic level of software testing that focuses on individual components. It is the smallest set of software tests. A unit refers to a small entity that it is important to test individually. Practical examples of units are functions, modules, sub-programs, classes and methods. In practice, unit testing focuses on a computer program's data structures and conditional and repeat structures.

The structure of computer program units changes as the development progresses, at which time unit tests must be modified or added. This is why unit testing is often automated using different tools.

Unit tests are designed and written by the software developer who created the unit, or a test designer or test specifier. Developing good test cases requires

• an understanding of requirements and plans
• knowledge of implementation and development tool use.

The purpose of integration testing is to assess how well different components work together. In practice, it means testing the APIs between units and their interaction. This involves technical testing to ensure that the units are compatible.

For example, one unit-tested component can be added to a functional configuration at a time, after which the functioning of the entire configuration can be ensured. This is why integration testing is often carried out together with unit testing.

It is a good practice for an organisation that has published an API for external users to also use this API in its own activities. This makes it easy for the organisation to notice any disruptions to the API.

For example, write rights or more extensive data processing rights can be offered for the organisation's internal use, while only read rights are available for external users.

Ready-made tools are available for testing APIs with OpenAPI descriptions. They test the API using its OpenAPI description. This makes significant automation of software testing possible.