[marketplace] Emit RequestFulfilled when all slots are filled

contracts/Marketplace.sol

@@ -9,6 +9,7 @@ contract Marketplace is Collateral, Proofs {
   uint256 public immutable collateral;
   MarketplaceFunds private funds;
   mapping(bytes32 => Request) private requests;
+  mapping(bytes32 => RequestState) private requestState;
   mapping(bytes32 => Slot) private slots;
 
   constructor(
@@ -65,8 +66,13 @@ contract Marketplace is Collateral, Proofs {
     _expectProofs(slotId, request.ask.proofProbability, request.ask.duration);
     _submitProof(slotId, proof);
 
+    RequestState storage state = requestState[requestId];
     slot.host = msg.sender;
+    state.slotsFilled += 1;
     emit SlotFilled(requestId, slotIndex, slotId);
+    if (state.slotsFilled == request.content.erasure.totalNodes) {
+      emit RequestFulfilled(requestId);
+    }
   }
 
   function payoutSlot(bytes32 requestId, uint256 slotIndex)
@@ -138,6 +144,10 @@ contract Marketplace is Collateral, Proofs {
     bytes name; // random name
   }
 
+  struct RequestState {
+    uint256 slotsFilled;
+  }
+
   struct Slot {
     address host;
     bool hostPaid;

test/Marketplace.test.js

@@ -231,4 +231,24 @@ describe("Marketplace", function () {
     })
   })
 
+  describe("fulfilling a request", function () {
+    beforeEach(async function () {
+      switchAccount(client)
+      await token.approve(marketplace.address, request.ask.reward)
+      await marketplace.requestStorage(request)
+      switchAccount(host)
+      await token.approve(marketplace.address, collateral)
+      await marketplace.deposit(collateral)
+    })
+
+    it("emits event when all slots are filled", async function () {
+      const lastSlot = request.content.erasure.totalNodes - 1
+      for (let i = 0; i < lastSlot; i++) {
+        await marketplace.fillSlot(slot.request, i, proof)
+      }
+      await expect(marketplace.fillSlot(slot.request, lastSlot, proof))
+        .to.emit(marketplace, "RequestFulfilled")
+        .withArgs(requestId(request))
+    })
+  })
 })