Called-on-contract example (TrueFiEng#288)

Fix contracts

examples/called-on-contract/.eslintrc.js

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+const baseConfig = require('../../.eslintrc.json')
+
+module.exports = {
+  ...baseConfig,
+}

examples/called-on-contract/.gitignore

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+node_modules
+build

examples/called-on-contract/package.json

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+{
+  "name": "example-basic",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "test": "export NODE_ENV=test && mocha",
+    "build": "waffle waffle.json",
+    "lint": "eslint '{src,test}/**/*.ts'",
+    "lint:fix": "eslint --fix '{src,test}/**/*.ts'"
+  },
+  "devDependencies": {
+    "@types/chai": "^4.2.3",
+    "@types/mocha": "^5.2.7",
+    "@typescript-eslint/eslint-plugin": "^2.30.0",
+    "@typescript-eslint/parser": "^2.30.0",
+    "chai": "^4.2.0",
+    "eslint": "^6.8.0",
+    "eslint-plugin-import": "^2.20.2",
+    "ethereum-waffle": "2.5.0",
+    "ethers": "4.0.47",
+    "mocha": "^7.1.2",
+    "ts-node": "^8.9.1",
+    "typescript": "^3.8.3",
+    "@openzeppelin/contracts": "^3.0.1"
+  }
+}

examples/called-on-contract/src/AmIRichAlready.sol

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+pragma solidity ^0.6.2;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+contract BasicToken is ERC20 {
+  constructor(uint256 initialBalance) ERC20("Basic", "BSC") public {
+    _mint(msg.sender, initialBalance);
+  }
+}
+
+contract AmIRichAlready {
+    BasicToken private tokenContract;
+    uint private constant RICHNESS = 1000000 * 10 ** 18;
+    constructor (BasicToken _tokenContract) public {
+        tokenContract = _tokenContract;
+    }
+
+    function check() public view returns (bool) {
+        uint balance = tokenContract.balanceOf(msg.sender);
+        return balance > RICHNESS;
+    }
+}

examples/called-on-contract/test/AmIRichAlready.test.ts

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+import {expect, use} from 'chai';
+import {Contract, utils} from 'ethers';
+import {deployContract, MockProvider, solidity} from 'ethereum-waffle';
+
+import BasicToken from '../build/BasicToken.json';
+import AmIRichAlready from '../build/AmIRichAlready.json';
+
+use(solidity);
+
+describe('Am I Rich Already', () => {
+  let ERC20: Contract;
+  let contract: Contract;
+  const [wallet] = new MockProvider().getWallets();
+
+  it('returns false if the wallet has less then 1000000 coins', async () => {
+    ERC20 = await deployContract(wallet, BasicToken, [utils.parseEther('999999')]);
+    contract = await deployContract(wallet, AmIRichAlready, [ERC20.address]);
+    expect(await contract.check()).to.be.equal(false);
+    expect('balanceOf').to.be.calledOnContract(ERC20);
+  });
+
+  it('returns true if the wallet has at least 1000000 coins', async () => {
+    ERC20 = await deployContract(wallet, BasicToken, [utils.parseEther('1000001')]);
+    contract = await deployContract(wallet, AmIRichAlready, [ERC20.address]);
+    expect(await contract.check()).to.equal(true);
+    expect('balanceOf').to.be.calledOnContractWith(ERC20, [wallet.address]);
+  });
+});

examples/called-on-contract/test/mocha.opts

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+-r ts-node/register/transpile-only
+--timeout 50000
+--no-warnings
+test/**/*.test.{js,ts}

examples/called-on-contract/tsconfig.json

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+{
+  "extends": "../../tsconfig.json"
+}

examples/called-on-contract/waffle.json

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+{
+  "compilerType": "solcjs",
+  "compilerVersion": "0.6.2",
+  "sourceDirectory": "./src",
+  "outputDirectory": "./build"
+}