Their test for "Set selectionStart and selectionEnd on a text field" tests that selection start and end can be set which should pass in Safari but their test fa

Their test for "Set selectionStart and selectionEnd on a text field" tests that selection start and end can be set which should pass in Safari but their test fails because they are asserting that window.getSelection().anchorNode == null after they've set the selection start and end points. This doesn't make sense to me and I don't get that from my reading of the spec. Am I missing something?