Owen Pryce

My two tests are validation and accuracy, and they fail independently, which is why a page can pass one and fail the other. Validation is mechanical. Required properties present, values of the right type, syntax correct. It is worth automating in a build step and worth running against the deployed page rather than the template, since a template can be correct while the rendered output carries a value a script overwrote. Accuracy is editorial. The markup has to describe what a reader can see on the page, because a mismatch between declared and visible content is treated as a reason to disregard both. A price, a rating or an availability that appears in the markup and not on the page is a fabricated claim whatever its source. Eligibility is a third question and it is not yours. A page can be valid and accurate and produce nothing, because the type has to be one the engine currently supports, and support changes. Types combine as separate blocks on one page: an article, a breadcrumb and a person, with an identifier linking them. The breadcrumb has to match the visible navigation rather than an idealised hierarchy, or the two contradict. I keep a note on each page of which types currently produce a result and which do not, because that changes and a stale note is worse than none. Maintenance is the part that goes wrong. Markup drifts as a template changes, values that were correct become stale, and a type that gained support months ago is still missing from pages written before it existed.