See quarto-dev/quarto#368 for context.

Both black and ruff format (and others) add spaces after single # starting a comment, so #| becomes # |. The Quarto VS Code extension supports formatting inside Python code chunks, so in general Quarto also supports # | for it's code cell metadata syntax.

#| test: one
# | test: two
##| test: three

# | test: one
# | test: two
##| test: three

In quarto-dev/quarto#368 (comment) I proposed Quarto also support ##|, since the formatters don't mess with that. I included support for that here, considering we already use ## file:.