These tests are for the proposal at WICG/origin-isolation. They should eventually move into a subdirectory of html/ if/when that proposal merges into the HTML Standard.
TODO: in whatwg/html#6214, the header was renamed from Origin-Isolation to Origin-Agent-Cluster, and the getter was renamed from window.originIsolated to window.originAgentCluster. The tests reflect this in their expectations, but all their messaging, names, and even the name of this folder, do not yet reflect it. That work is being tracked in https://crbug.com/1157917.
The tests in 2-iframes follow the file naming pattern
parent-[yes|no]-child1-[yes|no]-[designator]-child2-[yes|no]-[designator]
Here:
yes or no refers to whether the Origin-Isolation header is set or unset.designator explains how the child differs from the parent: e.g. by being a subdomain, or having a different port, or both. There‘s also same if it’s same-origin.Other directories have variations on this, e.g. 1-iframe/ does the same thing but for a single child instead of child1 and child2, and navigation/ uses 1 and 2 to represent the two different locations the single iframe will be navigated to.
Header parsing is covered by a few tests in the 1-iframe/ subdirectory, and not duplicated to all other scenarios.