Integration testing: steps toward SOA quality

Integration testing: The process of testing integrated servicesIntegration testing of a service should be performed by the QA/testing team and reviewed by both the architecture lead and development leads. At a minimum integration testing should consist of both verification of the integrated architectural design as it relates to the service under test and validation of integrated services. For each service this would consist of testing the functionality of the service and its relationship with all immediate (directly connected) services.
In our example, integration testing of the cart service would involve testing the cart service functionality and the integration of that service to the catalogue service, customer history service, digital fulfillment service, and the Web-enabled presentation layer. The purpose is to discover and address discrepancies between the functional specification and implementation of the cart service and its contractual responsibilities with other (immediate) services. Once again, this is especially important when implementing SOA.
The integration testing effort should focus on the service undergoing integration testing and its contractual responsibilities with other (immediate) services. There are several reasons for taking this approach, not the least of which is that integration testing of SOA solutions is extremely challenging -- the wider the scope of the integration testing effort, the more challenging it becomes. It useful to focus on the immediate landscape to ensure the contractual obligations are being met by each service and then extend the scope of testing during functional testing. The basic premise is to treat the services as building blocks that compose/support a particular business event or part of an event.
There are several automated SOA testing tools available (commercial and shareware) that help address the testing of services, and there are more traditional testing tools that can be tooled to address SOA testing. Many are able to capture service descriptions and create initial tests based on these descriptions. Those tests can then be automated.

Once you've completed integration testing of closely related services, you can begin true functional testing. This is where the real challenges of testing SOA solutions come to bear and involve the following:
· Third-party services
· Late binding (selection of service)
· Missing/incomplete/changing services
· Multi-platform/Multi-language distributed services