Add getHost() to retrieve host that fulfills request

contracts/Storage.sol

@@ -38,6 +38,10 @@ contract Storage is Collateral, Marketplace {
     return _request(id);
   }
 
+  function getHost(bytes32 id) public view returns (address) {
+    return _host(id);
+  }
+
   function finishContract(bytes32 id) public {
     require(_host(id) != address(0), "Contract not started");
     require(!contractFinished[id], "Contract already finished");

test/Storage.test.js

@@ -1,6 +1,7 @@
 const { expect } = require("chai")
 const { ethers, deployments } = require("hardhat")
 const { hexlify, randomBytes } = ethers.utils
+const { AddressZero } = ethers.constants
 const { exampleRequest } = require("./examples")
 const { advanceTime, advanceTimeTo, currentTime } = require("./evm")
 const { requestId } = require("./ids")
@@ -55,6 +56,12 @@ describe("Storage", function () {
     expect(retrieved.nonce).to.equal(request.nonce)
   })
 
+  it("can retrieve host that fulfilled request", async function () {
+    expect(await storage.getHost(requestId(request))).to.equal(AddressZero)
+    await storage.fulfillRequest(requestId(request), proof)
+    expect(await storage.getHost(requestId(request))).to.equal(host.address)
+  })
+
   describe("finishing the contract", function () {
     async function waitUntilEnd() {
       const end = (await storage.proofEnd(id)).toNumber()