This is a testharness.js-based test.
PASS Slots fallback: Basic.
FAIL Slots fallback: Basic, elements only. n.s1.assignedElements is not a function
PASS Slots fallback: Slots in Slots.
FAIL Slots fallback: Slots in Slots, elements only. n.s1.assignedElements is not a function
PASS Slots fallback: Fallback contents should not be used if a node is assigned.
PASS Slots fallback: Slots in Slots: Assigned nodes should be used as fallback contents of another slot
PASS Slots fallback: Complex case.
FAIL Slots fallback: Complex case, elements only. n.s1.assignedElements is not a function
PASS Slots fallback: Mutation. Append fallback contents.
PASS Slots fallback: Mutation. Remove fallback contents.
PASS Slots fallback: Mutation. Assign a node to a slot so that fallback contens are no longer used.
PASS Slots fallback: Mutation. Remove an assigned node from a slot so that fallback contens will be used.
PASS Slots fallback: Mutation.  Remove a slot which is a fallback content of another slot.
Harness: the test ran to completion.

