我怎样才能窥探与sinon的嵌套依赖

Question

我对mocha / chai / sinon很新，并且测试一般。我成功地测试了一个基本的快速服务器，一个返回承诺的函数，以及一个基本的续集设置来让我的鼻子湿透;但我被困在间谍/存根/嘲笑上。

我的第一个打嗝是试图检查外部模块中是否已调用blob：

//in utils.js
var glob = require('glob');

module.exports = {
  funToTest: function (msg, callback) {
    console.log(msg);
    glob('*md', {
      cwd: 'files/'
    }, function (err, files) {
      console.log(files);
    });
    callback();
    callback();
  }
};

使用mocha / chai / otherwise / if-chai组合：

// in utils-test.js
var utils = require('utils.js');
var glob = require('glob');

describe('Utils', function () {
  describe('funToTest method', function () {
    const callback = sinon.spy();
    const globSpy = sinon.spy(glob);

    before(function (done) {
      utils.funToTest('Files:', callback);
      done();
    });

    // This PASSES fine
    it ('should call our callback twice', function () {
      expect(callback).to.have.been.calledTwice;
    });

    // This NOT SO MUCH
    it('should call glob once', function () {
      expect(globSpy).to.have.been.calledOnce;
    });
  )};
)};

以上失败并出现断言错误：

AssertionError: expected glob to have been called exactly once, but it was called 0 times

那么我如何监视utils.funToTest中的glob依赖关系以查看是否被调用？

感谢任何指针......

Answer 1

你在监视glob模块本身，而不是你的funToTest方法中的glob调用。问题是glob调用是一个实现细节，实际上无法从测试中访问。你需要为glob回调传递一个参数并测试它是用spy还是stub调用的。

//in utils.js
var glob = require('glob');

module.exports = {
  funToTest: function (msg, globCb, callback) {
    glob('*md', {
      cwd: 'files/'
    }, globCb);
    callback();
    callback();
  }
};

// in utils-test.js
var utils = require('utils.js');
var glob = require('glob');

describe('Utils', function () {
  describe('funToTest method', function () {
    const callback = sinon.spy();
    const globCb = sinon.spy();

    const err = {err: 'Error'};
    const files = ['file1', 'file2'];

    before(function (done) {
      utils.funToTest('Files:', globCb, callback);
      done();
    });

    // Should still pass
    it ('should call our callback twice', function () {
      expect(callback).to.have.been.calledTwice;
    });

    // Passes with correct args
    it('should call glob once', function () {
      expect(globCb).to.have.been.calledOnce;
      // inspect the arg values with .calledWithArgs
      expect(globCb.calledWithArgs(err, files)).to.be.true;
      // inspect the arg values with .getCall(index) (actually grabs the call args on the first call to globSpy)
      expect(globCb.getCall(0).args[0]).to.equal(err);
      expect(globCb.getCall(0).args[1]).to.equal(files);
    });
  )};
)};