The TestController::defaultWebsiteDataStore() is created and used but never really assigned to the context. Since we are not assigning a WebsiteDataStore to the context, and we don't use the default WebsiteDataStore, when a new page is created, we end up creating the default one (with the default config, instead of the one created by WTR). We should set the TestController::defaultWebsiteDataStore() as the primary data store of the context like the GLib API does.
Created attachment 395672 [details] Patch
Comment on attachment 395672 [details] Patch Please make sure that tests pass before landing, otherwise LGTM.
Committed r259705: <https://trac.webkit.org/changeset/259705>
<rdar://problem/61433923>