account A
account B
commodity GBP

2012-03-25 GBP
    A            10.00 GBP
    B

2012-03-26 EUR
    A            20.00 EUR
    B

test bal --pedantic -> 1
__ERROR__
While parsing file "$FILE", line 10: 
While parsing posting:
  A            20.00 EUR
               ^^^^^^^^^
Error: Unknown commodity 'EUR'
end test