tests: blockchain model

package.json

@@ -1,22 +1,28 @@
 {
-  "name": "fxchain",
-  "version": "0.1.0",
-  "description": "The best blockchain in the world.",
-  "main": "src/index.ts",
-  "repository": "[email protected]:fgladisch/fxchain.git",
-  "author": "Felix Gladisch <[email protected]>",
-  "license": "MIT",
-  "private": false,
-  "devDependencies": {
-    "@types/node": "^9.6.0",
-    "tslint": "5.9.1",
-    "tslint-config-prettier": "^1.10.0",
-    "typescript": "2.7.2"
-  },
-  "scripts": {
-    "compile": "tsc"
-  },
-  "engines": {
-    "node": "^8 || ^9"
-  }
+	"name": "fxchain",
+	"version": "0.1.0",
+	"description": "The best blockchain in the world.",
+	"main": "src/index.ts",
+	"repository": "[email protected]:fgladisch/fxchain.git",
+	"author": "Felix Gladisch <[email protected]>",
+	"license": "MIT",
+	"private": false,
+	"devDependencies": {
+		"@types/chai": "4.1.2",
+		"@types/mocha": "5.0.0",
+		"@types/node": "9.6.0",
+		"chai": "4.1.2",
+		"mocha": "5.0.5",
+		"ts-node": "5.0.1",
+		"tslint": "5.9.1",
+		"tslint-config-prettier": "1.10.0",
+		"typescript": "2.7.2"
+	},
+	"scripts": {
+		"compile": "tsc",
+		"test": "mocha -r ts-node/register src/**/*.test.ts"
+	},
+	"engines": {
+		"node": "8 || 9"
+	}
 }

src/blockchain.model.test.ts

@@ -0,0 +1,40 @@
+import { assert } from "chai";
+
+import { Block } from "./block.model";
+import { Blockchain } from "./blockchain.model";
+
+const TEST_DATA: string = "TEST";
+
+describe("Blockchain", () => {
+	it("should create a new blockchain", () => {
+		const blockchain: Blockchain = new Blockchain();
+		assert.isDefined(blockchain.getGenesisBlock());
+	});
+
+	it("should create a blockchain with existing blocks", () => {
+		const testBlock: Block = new Block({
+			data: TEST_DATA,
+			index: 0,
+			previousHash: null
+		});
+		const blockchain: Blockchain = new Blockchain([testBlock]);
+		assert.equal(blockchain.getChain()[0], testBlock);
+	});
+
+	it("should generate a new block", () => {
+		const blockchain: Blockchain = new Blockchain();
+		blockchain.generateNextBlock(TEST_DATA);
+		const latestBlock: Block = blockchain.getLatestBlock();
+		assert.equal(latestBlock.data, TEST_DATA);
+	});
+
+	it("should overwrite the existing chain", () => {
+		const blockchain: Blockchain = new Blockchain();
+		blockchain.generateNextBlock(TEST_DATA);
+		const copy: Blockchain = new Blockchain([...blockchain.getChain()]);
+		copy.generateNextBlock(TEST_DATA);
+		assert.lengthOf(blockchain.getChain(), 2);
+		blockchain.replaceChain(copy.getChain());
+		assert.lengthOf(blockchain.getChain(), 3);
+	});
+});

src/blockchain.model.ts

@@ -1,5 +1,5 @@
 import { Block, BlockParams } from "./block.model";
-import { isValidChain, isValidNewBlock } from "./util/blockchain";
+import { isValidChain } from "./util/blockchain";
 import { calculateBlockHash } from "./util/crypto";
 
 const GENESIS_BLOCK_PARAMS: BlockParams = {
@@ -11,7 +11,7 @@ const GENESIS_BLOCK_PARAMS: BlockParams = {
 export class Blockchain {
 	private chain: Block[];
 
-	constructor(chain: Block[]) {
+	constructor(chain?: Block[]) {
 		if (chain) {
 			this.chain = chain;
 		} else {
@@ -47,9 +47,8 @@ export class Blockchain {
 	}
 
 	public replaceChain(newBlocks: Block[]): void {
-		if (isValidChain(this.chain[0], newBlocks) && newBlocks.length > this.chain.length) {
+		if (isValidChain(this.getGenesisBlock(), newBlocks) && newBlocks.length > this.chain.length) {
 			this.chain = newBlocks;
-			// TODO: broadcastLatest();
 		}
 	}
 }

src/util/blockchain.ts

@@ -7,10 +7,12 @@ export function isValidChain(genesis: Block, chain: Block[]): boolean {
 		return false;
 	}
 
-	return chain.reduce(
-		(valid, block) => isValidNewBlock(block, this.chain[block.index - 1]) || valid,
-		true
-	);
+	return chain.reduce((valid, block) => {
+		if (block.index === 0) {
+			return true;
+		}
+		return isValidNewBlock(block, chain[block.index - 1]) || valid;
+	}, true);
 }
 
 export function isValidNewBlock(newBlock: Block, previousBlock: Block): boolean {

src/util/crypto.ts

@@ -1,13 +1,12 @@
 import crypto = require("crypto");
 
-import { Block } from "./block.model";
+import { Block } from "../block.model";
 
 export function createHash(text: string): string {
 	return crypto
 		.createHash("sha256")
 		.update(text, "utf8")
-		.digest()
-		.toString();
+		.digest("hex");
 }
 
 export function calculateBlockHash({ index, previousHash, timestamp, data }: Block): string {

tsconfig.json

@@ -6,5 +6,5 @@
 		"outDir": "dist"
 	},
 	"include": ["src/**/*.ts"],
-	"exclude": ["node_modules"]
+	"exclude": ["node_modules", "src/**/*.test.ts"]
 }