emit DistributeRewards even when amount is 0

contracts/RewardsDistributor.sol

@@ -419,6 +419,8 @@ contract RewardsDistributor is IRewardsDistributor, Initializable, OwnableUpgrad
                 SQToken.safeTransfer(treasury, rewardsReturn);
                 emit ReturnRewards(runner, rewardsReturn, commission - cappedCommission);
             }
+        } else {
+            emit DistributeRewards(runner, rewardInfo.lastClaimEra, 0, 0);
         }
         return rewardInfo.lastClaimEra;
     }

test/RewardsBooster_migration.test.ts

@@ -683,7 +683,7 @@ describe('RewardsBooster Contract', () => {
             // 3 block passed (upgrade, migrateDeploymentBoost, collectAllocationReward) since we queried alReward0,
             // and 1 of them counts on old rewards, so we should get 500.5 SQT * 103 (availabe secs) / 1003 (total secs) = 51.397308075772681954
             // sometimes the test takes longer than 3 sec for 3 blocks, so result may become 52291
-            expect(evts[0].amount.div((1e15).toString()).toNumber()).to.within(51397, 52291);
+            expect(evts[0].amount.div((1e15).toString()).toNumber()).to.be.within(51397, 52291);
             // 1 block(collectAllocationReward) passed for new reward pool, so we should get 1.25 SQT more
             expect(evts[1].amount).to.lt(etherParse('1.25'));
             await blockTravel(999);

test/StateChannel.test.ts

@@ -656,7 +656,7 @@ describe('StateChannel Contract', () => {
             // reward distribution should be skipped due to total stake is 0
             tx = await rewardsHelper.connect(runner).indexerCatchup(runner.address);
             evt = await eventFrom(tx, rewardsDistributor, 'DistributeRewards(address,uint256,uint256,uint256)');
-            expect(evt).to.be.undefined;
+            expect(evt.rewards).to.eq(0);
         });
 
         /**
@@ -695,16 +695,18 @@ describe('StateChannel Contract', () => {
             await stateChannel.claim(channelId);
             balanceAfter = await token.balanceOf(consumer.address);
             expect(balanceBefore.sub(balanceAfter)).to.eq(etherParse('0.4'));
-            let evt = await eventFrom(tx, stateChannel, 'ChannelLabor2(uint256,bytes32,address,uint256)');
+            const evt = await eventFrom(tx, stateChannel, 'ChannelLabor2(uint256,bytes32,address,uint256)');
             expect(evt.amount).to.be.eq(etherParse('0.4'));
 
             // start new era so we can try collect the channel reward
             await startNewEra(eraManager);
 
             // reward distribution should be skipped due to total stake is 0
             tx = await rewardsHelper.connect(runner).indexerCatchup(runner.address);
-            evt = await eventFrom(tx, rewardsDistributor, 'DistributeRewards(address,uint256,uint256,uint256)');
-            expect(evt.rewards).to.eq(etherParse('0.4'));
+            const evts = await eventsFrom(tx, rewardsDistributor, 'DistributeRewards(address,uint256,uint256,uint256)');
+            expect(evts.length).to.eq(2);
+            expect(evts[0].rewards).to.eq(0);
+            expect(evts[1].rewards).to.eq(etherParse('0.4'));
 
             // delegator
             const delegatorRewards = await rewardsDistributor.userRewards(runner.address, delegator.address);