2018/01/01 * Opening Balance
    Assets:Checking                             $100.00
    Equity:Opening Balances

2018/01/01 * Budget
    [Assets:Checking]                           -$100.00
    [Assets:Budget:Food:Groceries]              $20.00
    [Assets:Budget:Food:Restaurants]            $80.00

2018/01/02 * Budget Groceries
    [Assets:Budget:Food:Groceries]              -$20 = $0
    [Assets:Checking]                           $20

2018/01/02 * Buy Groceries
    Assets:Checking                             -$20 = $80
    Expenses:Food:Groceries                     $20

test bal Assets
              $80.00  Assets:Budget:Food:Restaurants
end test

test bal Assets -R
              $80.00  Assets:Checking
end test