In this test, we create a complex Shadow DOM and try to drag from a div in nested shadow root of older shadow root to a div in nested shadow root of younger shadow root. Then we get selection from the following TreeScopes:
 * treeScopes[0] = document
 * treeScopes[1] = OLDER SHADOW ROOT
 * treeScopes[2] = YOUNGER SHADOW ROOT
 * treeScopes[3] = NESTED SHADOW ROOT IN OLDER SHADOW ROOT
 * treeScopes[4] = NESTED SHADOW ROOT IN YOUNGER SHADOW ROOT
and check selection.anchorNode, selection.focusNode, selection.baseNode, and selection.extentNode are null or in the same treescope.

Dragged from (DIV 2 IN NESTED SHADOW DOM OF OLDER SHADOW ROOT) to (DIV 2 IN NESTED SHADOW DOM OF YOUNGER SHADOW ROOT)

treeScopes[0] is document
PASS internals.treeScopeRootNode(treeScopes[0].getSelection().anchorNode) is document
PASS internals.treeScopeRootNode(treeScopes[0].getSelection().focusNode) is document
PASS internals.treeScopeRootNode(treeScopes[0].getSelection().baseNode) is document
PASS internals.treeScopeRootNode(treeScopes[0].getSelection().extentNode) is document

treeScopes[1] is OLDER SHADOW ROOT
PASS internals.treeScopeRootNode(treeScopes[1].getSelection().anchorNode) is treeScopes[1]
PASS internals.treeScopeRootNode(treeScopes[1].getSelection().focusNode) is treeScopes[1]
PASS internals.treeScopeRootNode(treeScopes[1].getSelection().baseNode) is treeScopes[1]
PASS internals.treeScopeRootNode(treeScopes[1].getSelection().extentNode) is treeScopes[1]

treeScopes[2] is YOUNGER SHADOW ROOT
Since treeScope[2] is outside of selection start point, no node should not be taken.
PASS treeScopes[2].getSelection().anchorNode is null
PASS treeScopes[2].getSelection().focusNode is null
PASS treeScopes[2].getSelection().baseNode is null
PASS treeScopes[2].getSelection().extentNode is null

treeScopes[3] is NESTED SHADOW ROOT IN OLDER SHADOW ROOT
PASS internals.treeScopeRootNode(treeScopes[3].getSelection().anchorNode) is treeScopes[3]
PASS internals.treeScopeRootNode(treeScopes[3].getSelection().focusNode) is treeScopes[3]
PASS internals.treeScopeRootNode(treeScopes[3].getSelection().baseNode) is treeScopes[3]
PASS internals.treeScopeRootNode(treeScopes[3].getSelection().extentNode) is treeScopes[3]

treeScopes[4] is NESTED SHADOW ROOT IN YOUNGER SHADOW ROOT
Since treeScope[4] is outside of selection start point, no node should not be taken.
PASS treeScopes[4].getSelection().anchorNode is null
PASS treeScopes[4].getSelection().focusNode is null
PASS treeScopes[4].getSelection().baseNode is null
PASS treeScopes[4].getSelection().extentNode is null

PASS successfullyParsed is true

TEST COMPLETE