Add a waitForTransaction to time helpers

The [hardhat-ethers](https://github.com/NomicFoundation/hardhat/blob/8f47553a88eb1251907398513449bc15689041d6/packages/hardhat-ethers/src/internal/hardhat-ethers-provider.ts#L362-L368) version is unimplemented, so we provide one.

src/index.ts

@@ -53,7 +53,7 @@ extendEnvironment((hre) => {
         return ownable(hre)
       }),
       time: lazyObject(() => {
-        return time()
+        return time(hre)
       }),
       signers: lazyObject(() => {
         return signers(hre)

src/time.ts

@@ -1,3 +1,4 @@
+import { HardhatRuntimeEnvironment } from "hardhat/types"
 import {
   mine,
   mineUpTo,
@@ -30,6 +31,8 @@ export interface HardhatTimeHelpers {
    * @param {number} blocks
    */
   mineBlocksTo(blocks: number): Promise<number>
+
+  waitForTransaction(txHash: string, confirmations?: number): Promise<boolean>
 }
 
 /**
@@ -86,12 +89,41 @@ export async function mineBlocksTo(targetBlock: number): Promise<number> {
   return await timeHelpers.latestBlock()
 }
 
-export default function (): HardhatTimeHelpers {
+export async function waitForTransaction(
+  hre: HardhatRuntimeEnvironment,
+  txHash: string,
+  confirmations: number = 1
+): Promise<boolean> {
+  if (hre.network.name === "hardhat") {
+    return true
+  }
+
+  const { provider } = hre.ethers
+  const transaction = await provider.getTransaction(txHash)
+  if (!transaction) {
+    throw new Error(`Transaction ${txHash} not found`)
+  }
+
+  let currentConfirmations = await transaction.confirmations()
+  while (currentConfirmations < confirmations) {
+    // wait 1s between each check to save API compute units
+    // eslint-disable-next-line no-await-in-loop, no-promise-executor-return
+    await new Promise((resolve) => setTimeout(resolve, 1000))
+    // eslint-disable-next-line no-await-in-loop
+    currentConfirmations = await transaction.confirmations()
+  }
+
+  return true
+}
+
+export default function (hre: HardhatRuntimeEnvironment): HardhatTimeHelpers {
   return {
     lastBlockNumber: () => lastBlockNumber(),
     lastBlockTime: () => lastBlockTime(),
     increaseTime: (time: number) => increaseTime(time),
     mineBlocks: (blocks: number) => mineBlocks(blocks),
     mineBlocksTo: (targetBlock: number) => mineBlocksTo(targetBlock),
+    waitForTransaction: (txHash: string, confirmations?: number) =>
+      waitForTransaction(hre, txHash, confirmations),
   }
 }

test/time.test.ts

@@ -1,11 +1,24 @@
 import { useEnvironment } from "./helpers"
 
 import type { HardhatTimeHelpers } from "../src/time"
+import type { HardhatEthersSigner } from "@nomicfoundation/hardhat-ethers/signers"
+import type { HardhatEthersHelpers } from "@nomicfoundation/hardhat-ethers/types"
+import type { ethers as ethersT } from "ethers"
+
+import { mine } from "@nomicfoundation/hardhat-network-helpers"
 
 import chai from "chai"
 chai.use(require("chai-as-promised"))
 const { expect } = chai
 
+function timeout(ms: number) {
+  return new Promise((resolve) => {
+    setTimeout(() => {
+      resolve("Timed out after " + ms + " ms")
+    }, ms)
+  })
+}
+
 describe("time helpers", function () {
   context("default hardhat project", function () {
     useEnvironment("hardhat-project")
@@ -114,5 +127,49 @@ describe("time helpers", function () {
         )
       })
     })
+
+    describe("waitForTransaction function", function () {
+      let ethers: typeof ethersT & HardhatEthersHelpers
+      let signer: HardhatEthersSigner
+      let transactionResponse: ethersT.TransactionResponse
+
+      beforeEach(async function () {
+        ethers = this.hre.ethers
+        signer = (await ethers.getSigners())[0]
+
+        const tx = {
+          to: signer.address, // Sending the transaction to the signer's own address
+          value: ethers.parseEther("0.01"), // Small amount of Ether, can also be 0
+        }
+        transactionResponse = await signer.sendTransaction(tx)
+      })
+
+      it("returns immediately on hardhat", async function () {
+        const waitResult = await Promise.race([
+          timeHelpers.waitForTransaction(transactionResponse.hash, 5),
+          timeout(300),
+        ])
+        expect(waitResult).to.be.true
+      })
+
+      it("does not return immediately on non-hardhat networks", async function () {
+        this.hre.network.name = "not-hardhat"
+        const waitResult = await Promise.race([
+          timeHelpers.waitForTransaction(transactionResponse.hash, 5),
+          timeout(1000),
+        ])
+        expect(waitResult).to.equal("Timed out after 1000 ms")
+      })
+
+      it("returns after the transaction is mined", async function () {
+        this.hre.network.name = "not-hardhat"
+        await mine(6)
+        const waitResult = await Promise.race([
+          timeHelpers.waitForTransaction(transactionResponse.hash, 5),
+          timeout(1000),
+        ])
+        expect(waitResult).to.be.true
+      })
+    })
   })
 })