Push Week 18

Week19/randomness/.editorconfig

@@ -0,0 +1,10 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.{js,json,yml}]
+charset = utf-8
+indent_style = space
+indent_size = 2

Week19/randomness/.gitignore

@@ -0,0 +1,23 @@
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/sdks
+!.yarn/versions
+
+# Swap the comments on the following lines if you don't wish to use zero-installs
+# Documentation here: https://yarnpkg.com/features/zero-installs
+!.yarn/cache
+#.pnp.*
+
+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+

Week19/randomness/.mocharc.json

@@ -0,0 +1,5 @@
+{
+    "require": "hardhat/register",
+    "timeout": 40000,
+    "_": ["tests/**/*.ts"]
+  }

Week19/randomness/.yarnrc.yml

@@ -0,0 +1,3 @@
+nodeLinker: node-modules
+
+yarnPath: .yarn/releases/yarn-3.5.1.cjs

Week19/randomness/README.md

@@ -0,0 +1,13 @@
+# Sample Hardhat Project
+
+This project demonstrates a basic Hardhat use case. It comes with a sample contract, a test for that contract, and a script that deploys that contract.
+
+Try running some of the following tasks:
+
+```shell
+npx hardhat help
+npx hardhat test
+REPORT_GAS=true npx hardhat test
+npx hardhat node
+npx hardhat run scripts/deploy.ts
+```

Week19/randomness/contracts/NotQuiteRandom.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >=0.7.0 <0.9.0;
+
+contract NotQuiteRandom {
+    function getRandomNumber()
+        public
+        view
+        returns (uint256 notQuiteRandomNumber)
+    {
+        // TODO: get randomness from block hash
+    }
+
+    function tossCoin() public view returns (bool heads) {
+        // TODO: make the random number be translated to a boolean
+    }
+}

Week19/randomness/hardhat.config.ts

@@ -0,0 +1,19 @@
+import { HardhatUserConfig, task } from "hardhat/config";
+import "@nomicfoundation/hardhat-toolbox";
+
+task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
+  const accounts = await hre.ethers.getSigners();
+
+  for (const account of accounts) {
+    console.log(account.address);
+    console.log(await account.getBalance());
+  }
+});
+
+const config: HardhatUserConfig = {
+  solidity: "0.8.18",
+  paths: { tests: "tests" },
+};
+
+export default config;
+

Week19/randomness/scripts/TestRandom.ts

@@ -0,0 +1,86 @@
+import { ethers } from "ethers";
+import { NotQuiteRandom } from "../typechain-types";
+
+async function blockHashRandomness() {
+  const contractFactory = await ethers.getContractFactory("NotQuiteRandom");
+  contractFactory.deploy().then(async (result) => {
+    result.deployed().then(async (contract: NotQuiteRandom) => {
+      const currentBlock = await ethers.provider.getBlock("latest");
+      const randomNumber = await contract.getRandomNumber();
+      console.log(
+        `Block number: ${currentBlock.number}\nBlock hash: ${currentBlock.hash}\nRandom number from this block hash: ${randomNumber}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock.timestamp + 1]);
+      const currentBlock2 = await ethers.provider.getBlock("latest");
+      const randomNumber2 = await contract.getRandomNumber();
+      console.log(
+        `Block number: ${currentBlock2.number}\nBlock hash: ${currentBlock2.hash}\nRandom number from this block hash: ${randomNumber2}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock2.timestamp + 1]);
+      const currentBlock3 = await ethers.provider.getBlock("latest");
+      const randomNumber3 = await contract.getRandomNumber();
+      console.log(
+        `Block number: ${currentBlock3.number}\nBlock hash: ${currentBlock3.hash}\nRandom number from this block hash: ${randomNumber3}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock3.timestamp + 1]);
+      const currentBlock4 = await ethers.provider.getBlock("latest");
+      const randomNumber4 = await contract.getRandomNumber();
+      console.log(
+        `Block number: ${currentBlock4.number}\nBlock hash: ${currentBlock4.hash}\nRandom number from this block hash: ${randomNumber4}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock4.timestamp + 1]);
+      const currentBlock5 = await ethers.provider.getBlock("latest");
+      const randomNumber5 = await contract.getRandomNumber();
+      console.log(
+        `Block number: ${currentBlock5.number}\nBlock hash: ${currentBlock5.hash}\nRandom number from this block hash: ${randomNumber5}`
+      );
+    });
+  });
+}
+
+async function tossCoin() {
+  const contractFactory = await ethers.getContractFactory("NotQuiteRandom");
+  contractFactory.deploy().then(async (result) => {
+    result.deployed().then(async (contract: NotQuiteRandom) => {
+      const currentBlock = await ethers.provider.getBlock("latest");
+      const heads = await contract.tossCoin();
+      console.log(
+        `Block number: ${currentBlock.number}\nBlock hash: ${
+          currentBlock.hash
+        }\nThe coin landed as: ${heads ? "Heads" : "Tails"}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock.timestamp + 1]);
+      const currentBlock2 = await ethers.provider.getBlock("latest");
+      const heads2 = await contract.tossCoin();
+      console.log(
+        `Block number: ${currentBlock2.number}\nBlock hash: ${
+          currentBlock2.hash
+        }\nThe coin landed as: ${heads2 ? "Heads" : "Tails"}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock2.timestamp + 1]);
+      const currentBlock3 = await ethers.provider.getBlock("latest");
+      const heads3 = await contract.tossCoin();
+      console.log(
+        `Block number: ${currentBlock3.number}\nBlock hash: ${
+          currentBlock3.hash
+        }\nThe coin landed as: ${heads3 ? "Heads" : "Tails"}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock3.timestamp + 1]);
+      const currentBlock4 = await ethers.provider.getBlock("latest");
+      const heads4 = await contract.tossCoin();
+      console.log(
+        `Block number: ${currentBlock4.number}\nBlock hash: ${
+          currentBlock4.hash
+        }\nThe coin landed as: ${heads4 ? "Heads" : "Tails"}`
+      );
+      await ethers.provider.send("evm_mine", [currentBlock4.timestamp + 1]);
+      const currentBlock5 = await ethers.provider.getBlock("latest");
+      const heads5 = await contract.tossCoin();
+      console.log(
+        `Block number: ${currentBlock5.number}\nBlock hash: ${
+          currentBlock5.hash
+        }\nThe coin landed as: ${heads5 ? "Heads" : "Tails"}`
+      );
+    });
+  });
+}

Week19/randomness/tests/Lock.ts

@@ -0,0 +1,124 @@
+import { time, loadFixture } from "@nomicfoundation/hardhat-network-helpers";
+import { anyValue } from "@nomicfoundation/hardhat-chai-matchers/withArgs";
+import { expect } from "chai";
+import { ethers } from "hardhat";
+
+describe("Lock", function () {
+  // We define a fixture to reuse the same setup in every test.
+  // We use loadFixture to run this setup once, snapshot that state,
+  // and reset Hardhat Network to that snapshot in every test.
+  async function deployOneYearLockFixture() {
+    const ONE_YEAR_IN_SECS = 365 * 24 * 60 * 60;
+    const ONE_GWEI = 1_000_000_000;
+
+    const lockedAmount = ONE_GWEI;
+    const unlockTime = (await time.latest()) + ONE_YEAR_IN_SECS;
+
+    // Contracts are deployed using the first signer/account by default
+    const [owner, otherAccount] = await ethers.getSigners();
+
+    const Lock = await ethers.getContractFactory("Lock");
+    const lock = await Lock.deploy(unlockTime, { value: lockedAmount });
+
+    return { lock, unlockTime, lockedAmount, owner, otherAccount };
+  }
+
+  describe("Deployment", function () {
+    it("Should set the right unlockTime", async function () {
+      const { lock, unlockTime } = await loadFixture(deployOneYearLockFixture);
+
+      expect(await lock.unlockTime()).to.equal(unlockTime);
+    });
+
+    it("Should set the right owner", async function () {
+      const { lock, owner } = await loadFixture(deployOneYearLockFixture);
+
+      expect(await lock.owner()).to.equal(owner.address);
+    });
+
+    it("Should receive and store the funds to lock", async function () {
+      const { lock, lockedAmount } = await loadFixture(
+        deployOneYearLockFixture
+      );
+
+      expect(await ethers.provider.getBalance(lock.address)).to.equal(
+        lockedAmount
+      );
+    });
+
+    it("Should fail if the unlockTime is not in the future", async function () {
+      // We don't use the fixture here because we want a different deployment
+      const latestTime = await time.latest();
+      const Lock = await ethers.getContractFactory("Lock");
+      await expect(Lock.deploy(latestTime, { value: 1 })).to.be.revertedWith(
+        "Unlock time should be in the future"
+      );
+    });
+  });
+
+  describe("Withdrawals", function () {
+    describe("Validations", function () {
+      it("Should revert with the right error if called too soon", async function () {
+        const { lock } = await loadFixture(deployOneYearLockFixture);
+
+        await expect(lock.withdraw()).to.be.revertedWith(
+          "You can't withdraw yet"
+        );
+      });
+
+      it("Should revert with the right error if called from another account", async function () {
+        const { lock, unlockTime, otherAccount } = await loadFixture(
+          deployOneYearLockFixture
+        );
+
+        // We can increase the time in Hardhat Network
+        await time.increaseTo(unlockTime);
+
+        // We use lock.connect() to send a transaction from another account
+        await expect(lock.connect(otherAccount).withdraw()).to.be.revertedWith(
+          "You aren't the owner"
+        );
+      });
+
+      it("Shouldn't fail if the unlockTime has arrived and the owner calls it", async function () {
+        const { lock, unlockTime } = await loadFixture(
+          deployOneYearLockFixture
+        );
+
+        // Transactions are sent using the first signer by default
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw()).not.to.be.reverted;
+      });
+    });
+
+    describe("Events", function () {
+      it("Should emit an event on withdrawals", async function () {
+        const { lock, unlockTime, lockedAmount } = await loadFixture(
+          deployOneYearLockFixture
+        );
+
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw())
+          .to.emit(lock, "Withdrawal")
+          .withArgs(lockedAmount, anyValue); // We accept any value as `when` arg
+      });
+    });
+
+    describe("Transfers", function () {
+      it("Should transfer the funds to the owner", async function () {
+        const { lock, unlockTime, lockedAmount, owner } = await loadFixture(
+          deployOneYearLockFixture
+        );
+
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw()).to.changeEtherBalances(
+          [owner, lock],
+          [lockedAmount, -lockedAmount]
+        );
+      });
+    });
+  });
+});

Week19/randomness/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "include": ["./scripts", "./tests", "./typechain-types"],
+  "files": ["./hardhat.config.ts"],
+  "compilerOptions": {
+    "target": "es2020",
+    "module": "commonjs",
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true,
+  }
+}