    @Test
    public void should_return_error_if_exchange_rate_not_available() {

        TransactionBuilder.withDb(db).account(a1).dateTime(DateTime.date(2012, 1, 10)).amount(1).create();

        assertFalse(c.getAccountBalance(c1, a1.id).isError()); // no conversion
        assertFalse(c.getAccountBalance(c3, a1.id).isError()); // all rates are available

        Total total = c.getAccountBalance(c2, a1.id);
        assertTrue(total.isError()); // no rate available on 10th

        total = c.getAccountBalance(c4, a1.id);
        assertTrue(total.isError());  // no rates at all
    }