[marketplace] require storage proofs when fulfilling request

contracts/Marketplace.sol

@@ -60,6 +60,11 @@ contract Marketplace is Collateral, Proofs {
     require(balanceOf(msg.sender) >= collateral, "Insufficient collateral");
     _lock(msg.sender, requestId);
 
+    _expectProofs(
+      requestId,
+      request.ask.proofProbability,
+      request.ask.duration
+    );
     _submitProof(requestId, proof);
 
     state.fulfilled = true;
@@ -123,6 +128,18 @@ contract Marketplace is Collateral, Proofs {
     return requestState[requestId].selectedOffer;
   }
 
+  function proofPeriod() public view returns (uint256) {
+    return _period();
+  }
+
+  function proofTimeout() public view returns (uint256) {
+    return _timeout();
+  }
+
+  function proofEnd(bytes32 contractId) public view returns (uint256) {
+    return _end(contractId);
+  }
+
   struct Request {
     address client;
     Ask ask;

contracts/Storage.sol

@@ -59,18 +59,6 @@ contract Storage is Collateral, Marketplace {
     require(token.transfer(offer.host, offer.price), "Payment failed");
   }
 
-  function proofPeriod() public view returns (uint256) {
-    return _period();
-  }
-
-  function proofTimeout() public view returns (uint256) {
-    return _timeout();
-  }
-
-  function proofEnd(bytes32 contractId) public view returns (uint256) {
-    return _end(contractId);
-  }
-
   function missingProofs(bytes32 contractId) public view returns (uint256) {
     return _missed(contractId);
   }

test/Marketplace.test.js

@@ -115,6 +115,11 @@ describe("Marketplace", function () {
       await expect(marketplace.withdraw()).to.be.revertedWith("Account locked")
     })
 
+    it("starts requiring storage proofs", async function () {
+      await marketplace.fulfillRequest(requestId(request), proof)
+      expect(await marketplace.proofEnd(requestId(request))).to.be.gt(0)
+    })
+
     it("is rejected when proof is incorrect", async function () {
       let invalid = hexlify([])
       await expect(