カバレッジが高いと品質が高い？Javascript / TypeScript のカバレッジを可視化して網羅する単体テストコード入門 ref: https://qiita.com/kasecato/items/1619b3e2c2e52c756736

coverageconfig.json

{
    "coverage": ["./coverage/lcov.info"],
    "sourcemapped": ["./out/src/*/**.js"],
    "automaticallyShow": true,
    "ignore": ["*.json"]
}

file0.txt

git clone https://github.com/kasecato/tscodecover.git
cd tscodecover
npm install
npm run build
code .

file1.txt

git clone https://github.com/bmeck/vscode-code-cover.git
cd vscode-code-cover/example/
npm install
npm run build
npm run coverage
code .

file10.txt

npm run build

file4.txt

npm install

file5.txt

npm install

file7.txt

./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report none -- --ui tdd ./out/test/**/*.js

file8.txt

./node_modules/.bin/nyc --reporter=lcovonly -- ./node_modules/.bin/mocha --ui tdd ./out/test/**/*.js

file9.txt

npm run build

NumberUtil.test.ts

import * as assert from 'assert';
import {NumberUtil} from '../../src/util/NumberUtil';

suite('NumberUtil Tests', () => {

    test('isOdd', () => {
        // arrange
        const n = 2501;

        // act
        const actual: boolean = NumberUtil.isOdd(n);

        // assert
        assert.equal(actual, true);
    });

});

NumberUtil.ts

export class NumberUtil {

    public static isOdd(n: number): boolean {
        if (n === undefined) {
            return false;
        } else if (n % 2 === 1) {
            return true;
        }
        return false;
    }

}

package.json

{
    "version": "2.0.0",
    "tasks": [
        {
            "type": "npm",
            "script": "build",
            "group": {
                "kind": "build",
                "isDefault": true
            }
        },
        {
            "type": "npm",
            "script": "coverage",
            "group": "test"
        }
    ]
}

プロジェクト構成

tscodecover/
├── .eslintrc.json
├── coverageconfig.json
├── package.json
├── tsconfig.json
|
├── .vscode/
|   └── tasks.json
├── coverage/
|   ├── coverage.json
|   └── lcov.info
├── src/
│   └── Util/
│       └── NumberUtil.ts
├── test/
│   └── Util/
│       └── NumberUtil.test.ts
└── out/