[VPD-612]: Increase TUSD supply cap on bsctestnet

simulations/vip-478/abi/comptroller.json

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+[
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "name": "supplyCaps",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "contract VToken[]",
+        "name": "vTokens",
+        "type": "address[]"
+      },
+      {
+        "internalType": "uint256[]",
+        "name": "newSupplyCaps",
+        "type": "uint256[]"
+      }
+    ],
+    "name": "_setMarketSupplyCaps",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  }
+]

simulations/vip-478/bsctestnet.ts

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+import { expect } from "chai";
+import { Contract } from "ethers";
+import { parseUnits } from "ethers/lib/utils";
+import { ethers } from "hardhat";
+import { NETWORK_ADDRESSES } from "src/networkAddresses";
+import { forking, testVip } from "src/vip-framework";
+
+import vip478, { NEW_SUPPLY_CAP, vTUSD } from "../../vips/vip-478/bsctestnet";
+import COMPTROLLER_ABI from "./abi/comptroller.json";
+
+const { bsctestnet } = NETWORK_ADDRESSES;
+
+const BLOCK_NUMBER = 91210770;
+
+forking(BLOCK_NUMBER, async () => {
+  let comptroller: Contract;
+
+  before(async () => {
+    comptroller = new ethers.Contract(bsctestnet.UNITROLLER, COMPTROLLER_ABI, ethers.provider);
+  });
+
+  describe("Pre-VIP behavior", async () => {
+    it("has the old supply cap for vTUSD", async () => {
+      const supplyCap = await comptroller.supplyCaps(vTUSD);
+      expect(supplyCap).to.be.equal(parseUnits("1000000", 18));
+    });
+  });
+
+  testVip("VIP-478 Risk Parameters Adjustments (FDUSD, TUSD)", await vip478());
+
+  describe("Post-VIP behavior", async () => {
+    it("has the new supply cap for vTUSD", async () => {
+      const supplyCap = await comptroller.supplyCaps(vTUSD);
+      expect(supplyCap).to.be.equal(NEW_SUPPLY_CAP);
+    });
+  });
+});

vips/vip-478/bsctestnet.ts

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+import { parseUnits } from "ethers/lib/utils";
+import { NETWORK_ADDRESSES } from "src/networkAddresses";
+import { ProposalType } from "src/types";
+import { makeProposal } from "src/utils";
+
+const { bsctestnet } = NETWORK_ADDRESSES;
+
+export const vTUSD = "0xEFAACF73CE2D38ED40991f29E72B12C74bd4cf23";
+export const OLD_SUPPLY_CAP = parseUnits("1000000", 18);
+export const NEW_SUPPLY_CAP = parseUnits("1000000000", 18);
+
+const vip478 = () => {
+  const meta = {
+    version: "v2",
+    title: "VIP-478 Risk Parameters Adjustments (FDUSD, TUSD)",
+    description: "Increase the supply cap for the TUSD market from 1,000,000 to 1,000,000,000",
+    forDescription: "I agree that Venus Protocol should proceed with this proposal",
+    againstDescription: "I do not think that Venus Protocol should proceed with this proposal",
+    abstainDescription: "I am indifferent to whether Venus Protocol proceeds or not",
+  };
+
+  return makeProposal(
+    [
+      {
+        target: bsctestnet.UNITROLLER,
+        signature: "_setMarketSupplyCaps(address[],uint256[])",
+        params: [[vTUSD], [NEW_SUPPLY_CAP]],
+      },
+    ],
+    meta,
+    ProposalType.REGULAR,
+  );
+};
+
+export default vip478;