The OPC Foundation provides test tools and certification for its specifications, and it is highly recommended that Companion Specifications also provide test cases. In addition to certification, testing is crucial for interoperability of OPC UA products. Each product designed to work with a Companion Specification needs to make sure the Companion Specification model is implemented correctly. Using the test tool and test cases provided by the OPC Foundation, automated testing can be carried out without additional need to create a testing environment. Testing and certification are based on Profiles and Facets. With actual test cases defined for each ConformanceUnit. Profiles and Facets can be nested and are composed of ConformanceUnits, a ConformanceUnit is the smallest testable item. The minimum test cases are checking the simple adherence to the defined information model (i.e., the instance correctly reflect the types it is based on). For Companion Specifications that describe expected functionality, it is important that test cases be created to test the defined functionality. For example, when a Method is defined in an information model, there is some expected behaviour associated with the Method and test cases are strongly recommended to be defined for this behaviour.

The OPC Foundation Certification working group (CMP) provides assistance to Companion Specification authors in defining and developing testing. The CMP group can provide an Excel Template that is filled out with test case definition. The CMP group can also provide examples of test cases defined for other companion standards.

It is highly recommended that development of test cases be started as soon as the information model starts to become stable. It is not uncommon for the process of defining test cases to identify modelling issues, such as minor issues just requiring clarifications in the text, but there may also be inconsistent definitions and unintended usage.

The CMP group can be reached at Compliance@opcfoundation.org