test: add tentative fork testing utils

tests/fork/utils/constants.ts

@@ -0,0 +1,13 @@
+export const ADDRESSES = {
+  bscmainnet: {
+    BUSD: "0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56",
+    USDT: "0x55d398326f99059fF775485246999027B3197955",
+    PancakeSwapRouter: "0x13f4EA83D0bd40E75C8222255bc855a974568Dd4",
+    MoveDebtDelegate: "0x89621C48EeC04A85AfadFD37d32077e65aFe2226",
+    Unitroller: "0xfD36E2c2a6789Db23113685031d7F16329158384",
+    NormalTimelock: "0x939bD8d64c0A9583A7Dcea9933f7b21697ab6396",
+    vUSDT: "0xfD5840Cd36d94D7229439859C0112a4185BC0255",
+    vBUSD: "0x95c78222B3D6e262426483D42CfA53685A67Ab9D",
+  },
+  bsctestnet: {},
+} as const;

tests/fork/utils/index.ts

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+import { impersonateAccount, setBalance } from "@nomicfoundation/hardhat-network-helpers";
+import { NumberLike } from "@nomicfoundation/hardhat-network-helpers/dist/src/types";
+import { ethers } from "hardhat";
+import hre from "hardhat";
+
+import { ADDRESSES } from "./constants";
+
+export type Network = keyof typeof ADDRESSES;
+export type ForkConfig<N extends Network> = { [T in N]: number };
+export type Addresses<N extends Network> = typeof ADDRESSES[N];
+
+export const resetFork = async (network: Network, blockNumber: number) => {
+  await hre.network.provider.request({
+    method: "hardhat_reset",
+    params: [
+      {
+        forking: {
+          jsonRpcUrl: process.env[`ARCHIVE_NODE_${network}`],
+          blockNumber,
+        },
+      },
+    ],
+  });
+};
+
+export const forking = <N extends Network>(config: ForkConfig<N>, fn: (addresses: Addresses<N>) => void) => {
+  if (!process.env.FORK || process.env.FORK === "false") {
+    return;
+  }
+  const config_ = Object.entries(config) as [N, number][];
+  config_.forEach(([network, blockNumber]) => {
+    describe(`Forking ${network} at block #${blockNumber}`, () => {
+      before(async () => {
+        await resetFork(network, blockNumber);
+      });
+      fn(ADDRESSES[network]);
+    });
+  });
+};
+
+export const initMainnetUser = async (user: string, balance?: NumberLike) => {
+  await impersonateAccount(user);
+  if (balance !== undefined) {
+    await setBalance(user, balance);
+  }
+  return ethers.getSigner(user);
+};