Ideographic, less than 4 spaces at end of line
Test passes if you see a single line with a single space after the character 行.
Assertion: The source text [ideographic characters + 3 spaces + line break + ideographic characters] will display as a single line with a single space before the second run of ideographic text.
The assumptions this test makes about expected behaviour are based on the white-space processing rules described in CSS3. The spaces at line end are not removed before line break transformation (LBT). LBT sees East Asian context on both sides so removes line break. Remaining spaces are then normalized to one space.