[Rewards] max limit parameter has no effect on fixed tax

[dkijania]

When using max_limit parameter along with fixed tax, reward mechanism does not take max_limit parameter value into account.

Example:
Given stake pool registration:

StakePool { ..., 
     rewards: TaxType { 
          fixed: Value(100), 
          ratio: Ratio { numerator: 0, denominator: 1 }, 
          max_limit: Some(30) 
     }, ....
 }

Actual reward: 100
Expected reward: 30

[rinor]

In some earlier conversations was pointed out that max_limit does not apply to the whole amount of the tax, but only to the ratio value. So the max expected total tax amount is fixed+max_limit and the min is fixed

[dkijania]

thanks, probably i missed that information. However, based on my tests i think min is not fixed it's: min(fixed,max_limit)

[dkijania]

If i have test like below:

let total_reward = 100;
let expected_stake_pool_reward = 10;
verify_distribute_rewards(
    total_reward,
    stake_pool("stake_pool").fixed_tax(10).tax_limit(5),
    expected_stake_pool_reward,
);

it fails due to assertion:
expected_stake_pool_reward != 5 (actual)