Node.js Unit Test Framework

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基于Node.js的 Unit Test Framework，用到了如下几个工具：

  • mocha: Mocha is a feature-rich JavaScript test framework.
  • sinon.js: Standalone test spies, stubs and mocks for JavaScript.
  • chai.js: Chai is a BDD / TDD assertion library.
  • supertest: Super-agent driven library for testing node.js HTTP servers using a fluent API.
  • istanbul.js: JavaScript test coverage made simple.

安装与配置

安装

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npm install mocha -S
npm install sinon -S
npm install chai -S
npm install supertest -S
npm install istanbul -S

配置

  1. 在项目的根目录下创建test文件夹，如果项目是分层结构的话可以在test下创建子目录
  2. 添加mocha启动命令，参数为需要扫描的含有unit test文件的文件夹
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mocha test/controller test/routes test/common test/service

为方便起见可以将命令添加到package.json

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"scripts": {
  "unit-test": "mocha test/controller test/routes test/common test/service"
}

编写 Unit Test

为方便查看unit test运行结果，可以采用每一个js文件对应一个Unit Test文件，每一个function对应一个组的结构来编写

Given-When-Then的case命名法

Definition

The Given-When-Then formula is a template intended to guide the writing of acceptance tests for a User Story:

  • Given: Set of preconditions
  • When: When an event occurs, or some action is carried out
  • Then: What outcome is achieved, or a particular set of observable consequences should obtain

Example：测试对象是人

  • Given：人的上下文预设：这是一个诗人
  • When：对人的操作：把这个人放在太平盛世中
  • Then：对人产生的结果：这个人将获得富足的生活
  • 则test case命名为：Given_一个人职业是诗人_When_活在太平盛世_Then_这个人生活富足

一个 test case的结构

一个test case分为3部分：

  1. mock函数部分
  2. Given步骤: 准备测试数据部分
  3. When步骤：调用测试函数
  4. Then步骤：断言返回结果

mocha中Unit Test的结构

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describe('userController', function() {
  describe('#findUserByPaging()', function() {
    // 准备测试数据
    ...
    // mock or stub function if need
    let sandbox;
    beforeEach(function() {
      sandbox = sinon.createSandbox();
    });
    afterEach(function() {
      sandbox.restore()
    });
    // test case
    it('should return limit user list when given offset limit', (done) => {
      userController.findUserByPaging(searchCriteria).then((result) => {
        // Then
        assert.equal(result.success, true) // assert断言
        done() // 表示一个Test Case结束
      }).catch((err) => {
        done(err) // 表示一个Test Case结束
      })
    })
  })
})

若断言不通过或者运行中抛出一个异常则会显示测试失败

Test Case Example

本例中用到的方法：

  • mocha:
    • describe()
    • done()
  • sinon.js
    • createSandbox()
    • stub
  • chai.js
    • assert.equal()
    • assert.deepEqual()
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describe('#findUserByPaging()', function() {
  let sandbox;
  // Given
  const searchResult = {
    "totalCount": 1,
    "data": [
      {
        "userId": 1,
        "userDomain": "TESTUSER",
        "userEmail": "test.user@outlook.com",
        "userTel": "1234567890",
        "userTeam": "MBC",
        "roleId": 1,
        "roleName": "Super Admin"
      }
    ]
  }
  const searchCriteria = {
    userDomain: 'TESTUSER',
    offset: 0,
    limit: 10
  }
  const expectData = {
    "data": [
      {
        "role": [
          {
            "roleId": 1,
            "roleName": "Super Admin"
          }
        ],
        "userDomain": "TESTUSER",
        "userEmail": "test.user@outlook.com",
        "userId": 1,
        "userTeam": "MBC",
        "userTel": "1234567890"
      }
    ],
    "limit": 10,
    "offset": 0,
    "totalCount": 1
  }
  // mock function
  beforeEach(function() {
    sandbox = sinon.createSandbox();
    sandbox.stub(UserRepo, "findUserByPaging").withArgs(sinon.match.any).returns(searchResult)
  });
  afterEach(function() {
    sandbox.restore()
  });
  it('should return limit user list when given offset limit', (done) => {
    // When
    userController.findUserByPaging(searchCriteria).then((result) => {
      // Then
      assert.equal(result.success, true)
      assert.deepEqual(result.data, expectData)
      done()
    }).catch((err) => {
      done(err)
    })
  })
})

对应上述代码：

  • Given部分给出了提供的数据，searchCriteria和searchResult对象
  • When部分调用了findUserByPaging方法
  • Then对返回结果进行了断言，判断了是否与预期结果expectData符合
  • 本例中对findUserByPaging方法所调用到的UserRepo对象的findUserByPaging方法进行了打桩并使其返回了我们对其预期的返回数据searchResult

mock or stub

如上述代码所示，使用到了sinon.js的createSandbox和stub方法

Default sandbox: Since sinon@5.0.0, the sinon object is a default sandbox. Unless you have a very advanced setup or need a special configuration, you probably want to just use that one.

与直接使用sinon.stub()比起来使用sandbox要更安全，而且在部分情况下前者会出现stub不掉的情况，而后者则不会

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"test should call all subscribers, even if there are exceptions" : function(){
    var message = 'an example message';
    var stub = sinon.stub().throws();
    var spy1 = sinon.spy();
    var spy2 = sinon.spy();

    PubSub.subscribe(message, stub);
    PubSub.subscribe(message, spy1);
    PubSub.subscribe(message, spy2);

    PubSub.publishSync(message, undefined);

    assert(spy1.called);
    assert(spy2.called);
    assert(stub.calledBefore(spy1));
}
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// Creates a new sandbox object with spies, stubs, and mocks.
var sandbox = sinon.createSandbox();
beforeEach(function() {
    sandbox = sinon.createSandbox();
    sandbox.stub(UserRepo, "findUserByPaging").withArgs(sinon.match.any).returns(searchResult)
});
afterEach(function() {
    sandbox.restore()
});

使用 supertest来编写模拟HTTP请求的 Unit Test

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describe('/nj_dom_notification/users/page', function() {
  let sandbox;
  const data = [
    {
      "userId": 1,
      "userDomain": "TESTUSER",
      "userEmail": "test.user@outlook.com",
      "userTel": "1234567890",
      "userTeam": "MBC",
      "role": [
        {
          "roleId": 1,
          "roleName": "Super Admin"
        }
      ]
    }
  ]
  beforeEach(function() {
    sandbox = sinon.createSandbox();
    sandbox.stub(userController, "findUserByPaging").callsFake(() => {
      return responseHelper.responsePageSuccess(data)
    })
  });
  afterEach(function() {
    sandbox.restore();
  });

  it('should get user list json when call findUserByPaging', (done) => {
    request(app)
      .get('/nj_dom_notification/users/page?userDomain=TESTUSER&limit=10&offset=0')
      .set('Accept', 'application/json')
      .expect('Content-Type', 'application/json; charset=utf-8')
      .expect(200, done)
      .expect(function(res) {
        assert.equal(res.body.success, true);
      })
  })
})

使用 Istanbul.js来统计 Unit Test的代码覆盖率

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{
 "scripts": {
   "unit-test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- test/controller test/routes test/common test/service"
 }
}

只需要在istanbul cover命令后面加上mocha的命令即可

若有不想统计的代码可以使用/* istanbul ignore next */注释来忽略掉，但是istanbul不支持文件忽略，只支持函数、选择条件级别的忽略。

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