Validator.nu Full-Stack Tests

Validator.nu has a framework for doing full-stack HTML5 validator testing in an implementation-independent manner. Currently, the framework is lacking tests.

The framework implements the design discussed at the HTML WG unconference session on validator testing at TPAC 2007.

The Front End

The front end for the system is the script named validator-tester.py in the test-harness/ directory.

The script is documented on a separate page.

The General Idea

The idea is to test the full validator through a Web service API in order to test the aggregation of software components running together with a realistic configuration. Testing merely the parser or the validation layer risks testing them in a different configuration than what gets deployed and without a real HTTP client connecting to real HTTP server.

The tests are intended to be implementation-independent for two reasons:

1. to make the tests reusable for different products
2. to avoid clamping down the implementation details within a product

There's no cross-product way to give identifiers to HTML5 errors. For example, the identification of errors pertaining to element nesting would be different in a grammar-based implementation and in an assertion-based implementation. Moreover, with grammar-based implementations, only the first error is reliable.

Therefore, the testing framework does not test for error identity. It only tests that the first error elicited by a test case falls within a specified source code character range. (This assumes that implementations can report error location, which is a bad assumption for validators that validate the DOM inside a browser, but we’d be left with no useful assumptions without this one.)

Thus, a test suite consists of files on a public HTTP server and a reference database of URIs pointing to the tests and expected locations of the first error for each URI.