Why does helix-core::test::print need to sometimes delete a newline?

[knottio]

helix-core::test::print sometimes deletes a newline from the string, as explained here:

helix/helix-core/src/test.rs

Lines 15 to 17 in 8e041c9

	/// If the selection contains any LF or CRLF sequences, which are immediately
	/// followed by the same grapheme, then the subsequent one is removed. This is
	/// to allow representing having the cursor over the end of the line.

But I can't think of any (String, Selection) pairs that can't be represented without having to delete a newline from the string. What pairs can't be represented?