2011-01-01 * Opening balance
    Assets:Cash                               10.00 GBP
    Equity:Opening balance                   -10.00 GBP

2011-02-01 * Buy 1 AAA for 10.00 GBP
    Assets:Investments                 1 AAA {10.00 GBP}
    Assets:Cash                              -10.00 GBP

2011-12-07 * Sell AAA with a gain
    Assets:Cash                               12.00 GBP
    Assets:Investments  -1 AAA {10.00 GBP} @@ 12.00 GBP
    Income:Capital gains                      -2.00 GBP

test bal
           12.00 GBP  Assets:Cash
          -10.00 GBP  Equity:Opening balance
           -2.00 GBP  Income:Capital gains
--------------------
                   0
end test