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Web Services Test Forum Announced

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Interoperability has always been one of the key factors pushed by vendors for the need for Web Services standards. There's even an organisation set up to address it. Over the past few years the various Web Services standards bodies such as OASIS and W3C have encouraged (mandated) interoperability demonstrations between heterogeneous vendor implementations before something can even be declared a standard. But one of the problems has always been that implementations change once these interop fests are completed and there is often limited (and ad hoc) approaches to continue to demonstrate interoperability. In recent weeks though we've seen a couple of new initiatives designed to try to bridge the gap. First there was the Apache Stonehenge project:

The aim of the Stonehenge project is to develop a set of sample applications to demonstrate seamless interoperability across multiple underlying platform technologies by using currently defined W3C and OASIS standard protocols.

And now there is the Web Services Test Forum (WSTF).

The WS Test Forum Group is meant to provide an environment in which members of the Web Service community can develop interop scenarios as well as test those scenarios against other Web Service implementations. It also provides a common testbed of regression tests that the community can use during the developmen of their Web Service implementations.

As Paul Krill reports:

Customers and vendors can dynamically test applications against implementations to ensure interoperability. Testing is intended to help delivery of higher quality products and open standards specifications to simplify integration and improve interoperability.

A definite plus point that WS-I, OASIS and W3C miss so far is the ability for members to publish in a central place their interoperability endpoints. Usually these things exist for the duration of the interoperability events and then disappear. But the obvious question is: how does it relate to WS-I? (Ignoring the apparent overlap with Stonehenge.) According to IBM's Karla Norsworthy:


We think WS-I has served us very well to define some of the profiles and focus on interoperability work for some of those basic profiles. [WSTF] is kind of an evolution.

The members stress that WSTF is meant to be more customer driven and dynamic, with a lightweight approach to defining what is tested and by whom. However, they also point out that this is definitely not a competitor to WS-I and those members who are involved there as well have indicated their intention to continue driving interoperability through that venue as well. Doug Davis from IBM points out in his article that ...

Simply providing a forum for people to ask questions and discuss ideas isn’t going to help solve interoperability issues. The forum needs to have a focus and purpose. That is the value provided by the WSTF's customer-focused scenarios. Unlike previous interoperability efforts, the WSTF is specifically designed to verify and examine scenarios and usage patterns that customers will actually use. The authors of the Web service specifications have always implicitly claimed to do this, but an examination of the rosters of the various standard authoring activities clearly reveals a lack of customer involvement. This inevitably leads to long protracted (and sometimes heated) discussions about what the specifications should, or should not, support. Disagreements over what the scenarios themselves should look like are also common. Having direct customer involvement in the discussion could go a long way towards reducing some of the tension and the length of the process.

Notable by their absence are Microsoft and Sun, both of whom have chosen not to participate at this point, indicating that their interoperability efforts will continue to be driven by involvement with WS-I. Given that Microsoft represents a large part of the Web Services market for many Web Services based integration needs, this can only limit the applicability of WSTF. It is interesting to note, however, that Microsoft do not seem to have a problem with juggling Stonehenge and WS-I participation so maybe their involved with WSTF is coming, because as Mike Champion from Microsoft says:

More generally, we believe that Stonehenge can help wire up the "last mile" between the standardized web services infrastructure that is now implemented across key platforms, and a new generation of service oriented applications that will span them. Existing WS-* interoperability work such of the sort done by WS-I and in our "plugfests" will continue to solidify the platform-level interoperability.  The new work, exemplified by Apache Stonehenge, should attract a wider community of users who can exploit the hard standardization and platform interoperability work without having to wallow in as many nasty details as in the past.

Which does sound like a similar goal for WSTF. In conclusion, Doug Davis makes it clear that WSTF is not limited to SOAP based Web Services:

[...] WSTF is actually not limited to just SOAP-based Web service testing. There is nothing that would prevent the WSTF to extend its testing into other Web service testing. For example, the WSTF would allow, and even encourage, the testing of domain-specific uses of SOAP/Web service. Testing of REST/Web services would also be allowed and will likely take place in the not too distant future. The WSTF isn’t just about SOAP-based interoperability testing—it’s about Web service interoperability testing, and the community itself will decide what that means over time.

On the basis that Web Services standards and implementations really live or die on their interoperability, the WSTF announcement is a good thing for customers, but only if all vendors agree to abide by it, or customers put it on their check-list of must-haves when selecting a specific vendor.

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