test.wikipedia.org is a test wiki inside the production cluster. It runs the same code as other Group 0 wikis.
Testwikis are intended primarily for:
- Short-term testing of code before pushing to other wikis. (see Debugging in production)
- Debugging issues in production.
- Long-term testing of configuration options or extensions that aren't enabled on other wikis.
- Testing global and cross-wiki features between test.wikipedia.org, test2.wikipedia.org, and/or test.wikidata.org.
test.wikipedia.org differs from test2.wikipedia.org in the following ways:
- Configuration enables
- Debug log instrumentation is enabled. Output from
wgDebugLog()is enabled (see Logs).
Until January 2016, traffic intended for test.wikipedia.org automatically got a
X-Wikimedia-Debug header set at the Varnish layer. This made all its requests automatically route to the canary server (mw1017, as of July 2013) for easy debugging in production. As all debug traffic, Varnish caching is automatically disabled for those test.wikipedia.org requests in Varnish.