Test passes if the two boxes below look exactly the same.

Key to entities used below: ‎ - LRM, the invisible left-to-right mark (strongly LTR). ‏ - RLM, the invisible right-to-left mark (strongly RTL). We use text-align:left because neither the dir="auto" nor the unicode-bidi:plaintext specification states whether text-align:start and text-align:end should obey the paragraph direction or the direction property in a unicode-bidi:plaintext element.
!‏123‎@ @‎123‏! !123‏‎@ @123‎‏!
@‎123‏! !‏123‎@ @123‎‏! !123‏‎@
!123@ !123@ !123@ !123@
@123! @123! @123! @123!