feat(tests): calculate maximum deviation for gas estimates

test/GasUsage.test.js

@@ -0,0 +1,171 @@
+const { ethers } = require("hardhat")
+const {
+  exampleRequest,
+  exampleProof,
+  exampleConfiguration,
+} = require("./examples")
+const { maxPrice } = require("./price")
+const { collateralPerSlot } = require("./collateral")
+const { requestId, slotId } = require("./ids")
+const {
+  revert,
+  snapshot,
+  ensureMinimumBlockHeight,
+  advanceTimeTo,
+  currentTime,
+} = require("./evm")
+const { expect } = require("chai")
+const { patchOverloads } = require("./marketplace")
+const { periodic } = require("./time")
+const { RequestState } = require("./requests")
+
+// Ensures that the actual gas costs can never deviate from the gas estimate by
+// more than a certain percentage.
+// The percentages from these tests should be used to pad the gas estimates in
+// market.nim, for example when calling fillSlot:
+// https://github.com/codex-storage/nim-codex/blob/6db6bf5f72a0038b77d02f48dcf128b4d77b469a/codex/contracts/market.nim#L278
+describe("Marketplace gas estimates", function () {
+  let marketplace
+  let token
+  let signer
+
+  async function setupToken() {
+    const Token = await ethers.getContractFactory("TestToken")
+    const token = await Token.deploy()
+    await token.mint(signer.address, 1_000_000_000_000_000)
+    return token
+  }
+
+  async function setupMarketplace() {
+    const Marketplace = await ethers.getContractFactory("Marketplace")
+    const Verifier = await ethers.getContractFactory("TestVerifier")
+    const verifier = await Verifier.deploy()
+    await ensureMinimumBlockHeight(256)
+    const marketplace = await Marketplace.deploy(
+      exampleConfiguration(),
+      token.address,
+      verifier.address
+    )
+    patchOverloads(marketplace)
+    return marketplace
+  }
+
+  async function requestStorage() {
+    const request = exampleRequest()
+    request.client = signer.address
+    await token.approve(marketplace.address, maxPrice(request))
+    await marketplace.requestStorage(request)
+    return request
+  }
+
+  async function startRequest(request) {
+    const id = requestId(request)
+    for (let i = 0; i < request.ask.slots; i++) {
+      await marketplace.reserveSlot(id, i)
+      await token.approve(marketplace.address, collateralPerSlot(request))
+      await marketplace.fillSlot(id, i, exampleProof())
+    }
+  }
+
+  beforeEach(async function () {
+    await snapshot()
+    signer = (await ethers.getSigners())[0]
+    token = await setupToken()
+    marketplace = await setupMarketplace()
+  })
+
+  afterEach(async function () {
+    await revert()
+  })
+
+  describe("reserveSlot", function () {
+    it("has at most 1% deviation in gas usage", async function () {
+      const request = await requestStorage()
+      const id = requestId(request)
+      const gasUsage = []
+      for (let i = 0; i < request.ask.slots; i++) {
+        const transaction = await marketplace.reserveSlot(id, i)
+        const receipt = await transaction.wait()
+        gasUsage.push(receipt.gasUsed.toNumber())
+        await token.approve(marketplace.address, collateralPerSlot(request))
+        await marketplace.fillSlot(id, i, exampleProof())
+      }
+      const deviation = Math.max(...gasUsage) / Math.min(...gasUsage) - 1.0
+      expect(deviation).to.be.gt(0)
+      expect(deviation).to.be.lte(0.01)
+    })
+  })
+
+  describe("fillSlot", function () {
+    it("has at most 10% deviation in gas usage", async function () {
+      const request = await requestStorage()
+      const id = requestId(request)
+      const gasUsage = []
+      for (let i = 0; i < request.ask.slots; i++) {
+        await marketplace.reserveSlot(id, i)
+        await token.approve(marketplace.address, collateralPerSlot(request))
+        const transaction = await marketplace.fillSlot(id, i, exampleProof())
+        const receipt = await transaction.wait()
+        gasUsage.push(receipt.gasUsed.toNumber())
+      }
+      const deviation = Math.max(...gasUsage) / Math.min(...gasUsage) - 1.0
+      expect(deviation).to.be.gt(0)
+      expect(deviation).to.be.lte(0.1)
+    })
+  })
+
+  describe("freeSlot", function () {
+    it("has at most 200% deviation in gas usage", async function () {
+      const request = await requestStorage()
+      const id = requestId(request)
+      await startRequest(request)
+      const gasUsage = []
+      for (let i = 0; i < request.ask.slots; i++) {
+        const slot = { request: id, index: i }
+        const transaction = await marketplace.freeSlot(slotId(slot))
+        const receipt = await transaction.wait()
+        gasUsage.push(receipt.gasUsed.toNumber())
+      }
+      const deviation = Math.max(...gasUsage) / Math.min(...gasUsage) - 1.0
+      expect(deviation).to.be.gt(0)
+      expect(deviation).to.be.lte(2.0)
+    })
+  })
+
+  describe("markProofAsMissing", function () {
+    let period, periodOf, periodEnd
+
+    beforeEach(async function () {
+      const configuration = await marketplace.configuration()
+      period = configuration.proofs.period
+      ;({ periodOf, periodEnd } = periodic(period))
+    })
+
+    it("has at most 50% deviation in gas usage", async function () {
+      const request = await requestStorage()
+      const id = requestId(request)
+      await startRequest(request)
+      const gasUsage = []
+      while ((await marketplace.requestState(id)) != RequestState.Failed) {
+        const missingPeriod = periodOf(await currentTime())
+        await advanceTimeTo(periodEnd(missingPeriod) + 1)
+        for (let i = 0; i < request.ask.slots; i++) {
+          try {
+            const slot = { request: id, index: i }
+            const transaction = await marketplace.markProofAsMissing(
+              slotId(slot),
+              missingPeriod
+            )
+            const receipt = await transaction.wait()
+            gasUsage.push(receipt.gasUsed.toNumber())
+          } catch (exception) {
+            // ignore: proof might not be missing
+          }
+        }
+      }
+      const deviation = Math.max(...gasUsage) / Math.min(...gasUsage) - 1.0
+      expect(deviation).to.be.gt(0)
+      expect(deviation).to.be.lte(0.5)
+    })
+  })
+})