move operator from staking logic to vault, allow operator to decrease operatorShare

contracts/staking/test/actors/pool_operator_actor.ts

@@ -86,4 +86,26 @@ export class PoolOperatorActor extends BaseActor {
         );
         expect(poolIdOfMakerAfterRemoving, 'pool id of maker').to.be.equal(stakingConstants.NIL_POOL_ID);
     }
+    public async decreaseStakingPoolOperatorShareAsync(
+        poolId: string,
+        newOperatorShare: number,
+        revertError?: RevertError,
+    ): Promise<void> {
+        // decrease operator share
+        const txReceiptPromise = this._stakingApiWrapper.stakingContract.decreaseStakingPoolOperatorShare.awaitTransactionSuccessAsync(
+            poolId,
+            newOperatorShare,
+            { from: this._owner },
+        );
+        if (revertError !== undefined) {
+            await expect(txReceiptPromise).to.revertWith(revertError);
+            return;
+        }
+        await txReceiptPromise;
+        // Check operator share
+        const decreasedOperatorShare = await this._stakingApiWrapper.rewardVaultContract.getOperatorShare.callAsync(
+            poolId,
+        );
+        expect(decreasedOperatorShare, 'updated operator share').to.be.bignumber.equal(newOperatorShare);
+    }
 }