ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

$ npm install truffle-hdwallet-provider
$ truffle compile

truffleconfig.js

const HDWalletProvider = require("truffle-hdwallet-provider");
const mnemonic = "";

    ropsten: {
      provider: () => new HDWalletProvider(mnemonic, `https://ropsten.infura.io/v3/${project_id}`),
      network_id: 3,       // Ropsten's id
      gas: 5500000,        // Ropsten has a lower block limit than mainnet
      confirmations: 2,    // # of confs to wait between deployments. (default: 0)
      timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
      skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
    },

$ truffle migrate –network ropsten

なるほど、これは凄い

Practice.sol
L 構造体Clientのclientsという配列に格納して、excesise関数でweightを-2として返却するコントラクトです。

pragma solidity >= 0.4.0 < 0.7.0;

contract Practice {

	struct Client {
		string name;
		string gender;
		uint256 weight;
		uint256 height;
	}
	Client[] public clients;

	function register(string memory _name, string memory _gender, uint256 _weight, uint256 _height) public returns(uint256 id) {
		id = clients.push(Client(_name, _gender, _weight, _height)) - 1;
		return id;
	}

	function excesise() public returns (uint256 newWeight){
		newWeight = clients[0].weight - 2;
		return newWeight;
	}

}

practice_test.js

	describe("practice()", () => {
		it("returns excesized weight", async() => {
			const practice = await PracticeContract.deployed();
			const expected = 63;
			await practice.register("yamada", "male", 65, 175);
			const actual = await practice.excesise.call();
			
			assert.equal(actual, expected, "Weight should be 63");
		})
	})

Contract: Practice
✓ has been deployed successfully
practice()
✓ returns weight (124ms)

2 passing (184ms)

Practice.sol

contract Practice {

	function hello() external pure returns(string memory) {
		return "Hello, World!";
	}

	function tax(uint256 price) public pure returns(uint256 newPrice){
		 newPrice = price * 11 / 10;
		 return newPrice;
	}
}

practice_test.js

	describe("practice()", () => {
		it("returns tax in price", async() => {
			const practice = await PracticeContract.deployed();
			const expected = "110";
			const actual = await practice.tax(100);
			assert.equal(actual, expected, "should be 110");
		})
	})

$ truffle test

Compiling your contracts…
===========================
> Compiling ./contracts/Migrations.sol
> Compiling ./contracts/Practice.sol
> Artifacts written to /tmp/test-202209-108928-12xhvrv.xr0d
> Compiled successfully using:
– solc: 0.5.16+commit.9c3226ce.Emscripten.clang

Contract: Practice
✓ has been deployed successfully
practice()
✓ returns ‘Hello, World!’
practice()
✓ returns tax in price

3 passing (123ms)

taxのmultiplyは　price * 1.1; とするとエラーになるので、price * 11 / 10;としないといけない。
なるほど、中々激しい。