Add ability to slash expenditure stakes

Author: kronosapiens

contracts/extensions/ExpenditureUtils.sol

@@ -37,7 +37,7 @@ contract ExpenditureUtils is ColonyExtensionMeta, PatriciaTreeProofs {
   // Modifiers
 
   modifier onlyRoot() {
-    require(colony.hasUserRole(msgSender(), 1, ColonyDataTypes.ColonyRole.Root), "voting-rep-caller-not-root");
+    require(colony.hasUserRole(msgSender(), 1, ColonyDataTypes.ColonyRole.Root), "evaluated-expenditure-caller-not-root");
     _;
   }
 
@@ -102,6 +102,26 @@ contract ExpenditureUtils is ColonyExtensionMeta, PatriciaTreeProofs {
     colony.transferExpenditure(expenditureId, msgSender());
   }
 
+  function slashStake(
+    uint256 _permissionDomainId,
+    uint256 _childSkillIndex,
+    uint256 _expenditureId
+  )
+    public
+  {
+    ColonyDataTypes.Expenditure memory expenditure = colony.getExpenditure(_expenditureId);
+    uint256 stake = stakes[expenditure.owner][_expenditureId];
+    require(stake > 0, "expenditure-utils-nothing-to-claim");
+
+    require(
+      colony.hasInheritedUserRole(msgSender(), _permissionDomainId, ColonyDataTypes.ColonyRole.Arbitration, _childSkillIndex, expenditure.domainId),
+      "expenditure-utils-caller-not-arbitration"
+    );
+
+    delete stakes[expenditure.owner][_expenditureId];
+    colony.transferStake(_permissionDomainId, _childSkillIndex, address(this), expenditure.owner, expenditure.domainId, stake, address(0x0));
+  }
+
   function reclaimStake(uint256 _expenditureId) public {
     uint256 stake = stakes[msgSender()][_expenditureId];
     require(stake > 0, "expenditure-utils-nothing-to-claim");

test/extensions/expenditure-utils.js

@@ -113,7 +113,7 @@ contract("ExpenditureUtils", (accounts) => {
     });
   });
 
-  describe.only("using stakes to manage expenditures", async () => {
+  describe("using stakes to manage expenditures", async () => {
     beforeEach(async () => {
       await expenditureUtils.setStakeFraction(WAD.divn(10)); // Stake of .3 WADs
 
@@ -134,6 +134,19 @@ contract("ExpenditureUtils", (accounts) => {
       expect(obligation).to.eq.BN(WAD.muln(3).divn(10));
     });
 
+    it("can slash the stake with the arbitration permission", async () => {
+      await expenditureUtils.makeExpenditureWithStake(1, UINT256_MAX, 1, domain1Key, domain1Value, domain1Mask, domain1Siblings, { from: USER0 });
+      const expenditureId = await colony.getExpenditureCount();
+
+      await expenditureUtils.slashStake(1, UINT256_MAX, expenditureId);
+
+      const obligation = await tokenLocking.getObligation(USER0, token.address, colony.address);
+      expect(obligation).to.be.zero;
+
+      const userLock = await tokenLocking.getUserLock(token.address, USER0);
+      expect(userLock.balance).to.eq.BN(WAD.sub(WAD.muln(3).divn(10)));
+    });
+
     it("can reclaim the stake by cancelling the expenditure", async () => {
       await expenditureUtils.makeExpenditureWithStake(1, UINT256_MAX, 1, domain1Key, domain1Value, domain1Mask, domain1Siblings, { from: USER0 });
       const expenditureId = await colony.getExpenditureCount();
@@ -144,6 +157,9 @@ contract("ExpenditureUtils", (accounts) => {
 
       const obligation = await tokenLocking.getObligation(USER0, token.address, colony.address);
       expect(obligation).to.be.zero;
+
+      const userLock = await tokenLocking.getUserLock(token.address, USER0);
+      expect(userLock.balance).to.eq.BN(WAD);
     });
 
     it("can reclaim the stake by finalizing the expenditure", async () => {
@@ -156,6 +172,9 @@ contract("ExpenditureUtils", (accounts) => {
 
       const obligation = await tokenLocking.getObligation(USER0, token.address, colony.address);
       expect(obligation).to.be.zero;
+
+      const userLock = await tokenLocking.getUserLock(token.address, USER0);
+      expect(userLock.balance).to.eq.BN(WAD);
     });
 
     it("cannot reclaim the stake while the expenditure is in progress", async () => {