Michael and a tiny XML Schema test suite

C. M. Sperberg-McQueen has opened a blog recently, Message in a bottle. It is really cool. When I had questions about XML, I sometimes asked him on the W3C internal mailing-lists. Very often, I thought that it would be great if his answers were public. Not only, he knows XML, but his replies are very clear.

Two days ago in a message, Sandboxes and test cases about XML Schemas tests, he’s telling about the process of creating test cases and trying in some implementations.

It’s always interesting to construct test cases to illustrate some question or other that arises, whether from a comment on the spec or an inquiry by email. And I have directories with scores of small test cases I have constructed over the last few years. But until I started this more systematic construction of a schema validation sandbox, I contented myself with checking those test cases with one or two processors.

But also explains that playing with more tools is more fun.

But it turns out that having more processors to test is just a lot more fun. Here is a test case. OK, what does libxml say about it? MSV? Saxon? Xerces C? Xerces J?

Identifying issues in software helps people to improve implementations and specifications. But if you do so, please be kind. It is always better and more encouraging to receive an email saying “I may have identified an issue” more than “Dude. I broke your implementation. Take that!”. It might sound silly but courtesy helps a lot to get things fixed.

Back to the article of Michael, he has been publishing a tiny collection of XML Schema test cases. And as he said:

I plan to put every schema example I generate this year there, instead of hiding it on my hard disk. At least the interesting ones.

Well done Michael and happy new year too.