This is a testharness.js-based test.
PASS idl_test setup
PASS idl_test validation
PASS Partial namespace CSS: original namespace defined
PASS Partial namespace CSS: member names are unique
PASS CSS namespace: operation escape(CSSOMString)
FAIL CSS namespace: attribute elementSources assert_own_property: CSS does not have property "elementSources" expected property "elementSources" missing
Harness: the test ran to completion.