allow VP with no fee

ethereum/contracts/Rollup.sol

@@ -121,6 +121,7 @@ contract Rollup is Availability {
 
     /// If the batch worker fails to submit the batch, a new batch worker may be selected
     function resetBatchWorker() public {
+        // TODO: Grace period after the current batch is due and before the worker can be replaced
         require(
             block.timestamp - batchStart > batchInterval,
             "Current batch interval has not yet elapsed"
@@ -131,7 +132,8 @@ contract Rollup is Availability {
                 block.timestamp - lastWorkerReset >= minResetInterval,
             "Mininum reset interval has not elapsed since last batch worker reset"
         );
-        // TODO: Should the current batch worker's availability stakes be forfeit?
+        // TODO: Submit a validation pool targeting a null post, and send the worker's availability stake
+        // This gives the DAO an opportunity to police the failed work
         // Select a new batch worker
         batchWorkerStakeIndex = assignWork();
         batchWorker = stakes[batchWorkerStakeIndex].worker;

ethereum/contracts/core/Bench.sol

@@ -97,7 +97,6 @@ contract Bench {
             msg.sender == address(dao),
             "Only DAO contract may call initiateValidationPool"
         );
-        require(msg.value > 0, "Fee is required to initiate validation pool");
         require(duration >= minDuration, "Duration is too short");
         require(duration <= maxDuration, "Duration is too long");
         require(
@@ -124,7 +123,7 @@ contract Bench {
         // We use our privilege as the DAO contract to mint reputation in proportion with the fee.
         // Here we assume a minting ratio of 1
         // TODO: Make minting ratio an adjustable parameter
-        dao.mint(address(dao), msg.value);
+        dao.mint(address(dao), pool.props.fee);
         pool.props.minted = msg.value;
         dao.emitValidationPoolInitiated(poolIndex);
     }

ethereum/test/ValidationPools.js

@@ -52,9 +52,9 @@ describe('Validation Pools', () => {
   });
 
   describe('Initiate', () => {
-    it('should not be able to initiate a validation pool without a fee', async () => {
+    it('should be able to initiate a validation pool without a fee', async () => {
       const init = () => initiateValidationPool({ fee: 0 });
-      await expect(init()).to.be.revertedWith('Fee is required to initiate validation pool');
+      await expect(init()).to.emit(dao, 'ValidationPoolInitiated');
     });
 
     it('should not be able to initiate a validation pool with a quorum below the minimum', async () => {