js-spy/src/chai/chai-spies-plugin.js

/* eslint-disable jsdoc/require-jsdoc */

/**
 * Chai spies plugin
 *
 * @param {*} chai
 * @param {*} _
 */
/* prettier-ignore */
export function chaiSpiesPlugin(chai, _) {
  const Assertion = chai.Assertion;

  Assertion.addProperty('spy', function () {
    this.assert(
        this._obj.__isSpy === true
      , 'expected ' + this._obj + ' to be a spy'
      , 'expected ' + this._obj + ' to not be a spy');
    return this;
  });

  function assertCalled (n) {
    new Assertion(this._obj).to.be.spy;
    const spy = this._obj;

    if (n != undefined) {
      this.assert(
          spy.calls.length === n
        , 'expected ' + this._obj + ' to have been called #{exp} but got #{act}'
        , 'expected ' + this._obj + ' to have not been called #{exp}'
        , n
        , spy.calls.length
      );
    } else {
      this.assert(
          spy.called === true
        , 'expected ' + this._obj + ' to have been called'
        , 'expected ' + this._obj + ' to not have been called'
      );
    }
  }

  function assertCalledChain () {
    new Assertion(this._obj).to.be.spy;
  }

  Assertion.addChainableMethod('called', assertCalled, assertCalledChain);

  Assertion.addProperty('once', function () {
    new Assertion(this._obj).to.be.spy;
    this.assert(
        this._obj.calls.length === 1
      , 'expected ' + this._obj + ' to have been called once but got #{act}'
      , 'expected ' + this._obj + ' to not have been called once'
      , 1
      , this._obj.calls.length );
  });

  Assertion.addProperty('twice', function () {
    new Assertion(this._obj).to.be.spy;
    this.assert(
        this._obj.calls.length === 2
      , 'expected ' + this._obj + ' to have been called twice but got #{act}'
      , 'expected ' + this._obj + ' to not have been called twice'
      , 2
      , this._obj.calls.length
    );
  });

  function nthCallWith(spy, n, expArgs) {
    if (spy.calls.length <= n) return false;
    const actArgs = spy.calls[n].args;
    if (actArgs.length !== expArgs.length) return false;
    // проверка каждого ожидаемого аргумента на строгое
    // соответствие позиции и значения
    for (let i = 0; i < expArgs.length; i++) {
      if (!_.eql(actArgs[i], expArgs[i])) {
        return false;
      }
    }
    return true;
  }

  function numberOfCallsWith(spy, expArgs) {
    let found = 0;
    const calls = spy.calls;

    for (let i = 0; i < calls.length; i++) {
      if (nthCallWith(spy, i, expArgs)) {
        found++;
      }
    }

    return found;
  }

  Assertion.addProperty('first', function () {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy nth call with', 1);
    }
  });

  Assertion.addProperty('second', function () {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy nth call with', 2);
    }
  });

  Assertion.addProperty('third', function () {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy nth call with', 3);
    }
  });

  Assertion.addProperty('on');

  Assertion.addChainableMethod('nth', function (n) {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy nth call with', n);
    }
  });

  function generateOrdinalNumber(n) {
    if (n === 1) return 'first';
    if (n === 2) return 'second';
    if (n === 3) return 'third';
    return n + 'th';
  }

  function assertWith() {
    new Assertion(this._obj).to.be.spy;
    const expArgs = [].slice.call(arguments, 0)
      , spy = this._obj
      , calls = spy.calls
      , always = _.flag(this, 'spy always')
      , nthCall = _.flag(this, 'spy nth call with');

    if (always) {
      const passed = numberOfCallsWith(spy, expArgs);
      this.assert(
          arguments.length
            ? calls.length && passed === calls.length
            : calls.length === 0
        , 'expected ' + this._obj + ' to have been always called with #{exp} but got ' + passed + ' out of ' + calls.length
        , 'expected ' + this._obj + ' to have not always been called with #{exp}'
        , expArgs
      );
    } else if (nthCall) {
      const ordinalNumber = generateOrdinalNumber(nthCall),
          actArgs = calls[nthCall - 1];
      new Assertion(this._obj).to.be.have.been.called.min(nthCall);
      this.assert(
          nthCallWith(spy, nthCall - 1, expArgs)
        , 'expected ' + this._obj + ' to have been called at the ' + ordinalNumber + ' time with #{exp} but got #{act}'
        , 'expected ' + this._obj + ' to have not been called at the ' + ordinalNumber + ' time with #{exp}'
        , expArgs
        , actArgs
      );
    } else {
      const passed = numberOfCallsWith(spy, expArgs);
      this.assert(
          passed > 0
        , 'expected ' + this._obj + ' to have been called with #{exp}'
        , 'expected ' + this._obj + ' to have not been called with #{exp} but got ' + passed + ' times'
        , expArgs
      );
    }
  }

  function assertWithChain () {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy with', true);
    }
  }

  Assertion.addChainableMethod('with', assertWith, assertWithChain);

  Assertion.addProperty('always', function () {
    if (this._obj.__isSpy) {
      _.flag(this, 'spy always', true);
    }
  });

  Assertion.addMethod('exactly', function () {
    new Assertion(this._obj).to.be.spy;
    const args = [].slice.call(arguments, 0);
    this.assert(
        this._obj.calls.length === args[0]
      , 'expected ' + this._obj + ' to have been called #{exp} times but got #{act}'
      , 'expected ' + this._obj + ' to not have been called #{exp} times'
      , args[0]
      , this._obj.calls.length
    );
  });

  function above (_super) {
    return function (n) {
      if (this._obj.__isSpy) {
        new Assertion(this._obj).to.be.spy;

        this.assert(
            this._obj.calls.length > n
          , 'expected ' + this._obj + ' to have been called more than #{exp} times but got #{act}'
          , 'expected ' + this._obj + ' to have been called at most #{exp} times but got #{act}'
          , n
          , this._obj.calls.length
        );
      } else {
        _super.apply(this, arguments);
      }
    }
  }

  Assertion.overwriteMethod('above', above);
  Assertion.overwriteMethod('gt', above);

  function below (_super) {
    return function (n) {
      if (this._obj.__isSpy) {
        new Assertion(this._obj).to.be.spy;

        this.assert(
            this._obj.calls.length <  n
          , 'expected ' + this._obj + ' to have been called fewer than #{exp} times but got #{act}'
          , 'expected ' + this._obj + ' to have been called at least #{exp} times but got #{act}'
          , n
          , this._obj.calls.length
        );
      } else {
        _super.apply(this, arguments);
      }
    }
  }

  Assertion.overwriteMethod('below', below);
  Assertion.overwriteMethod('lt', below);

  function min (_super) {
    return function (n) {
      if (this._obj.__isSpy) {
        new Assertion(this._obj).to.be.spy;

        this.assert(
            this._obj.calls.length >= n
          , 'expected ' + this._obj + ' to have been called at least #{exp} times but got #{act}'
          , 'expected ' + this._obj + ' to have been called fewer than #{exp} times but got #{act}'
          , n
          , this._obj.calls.length
        );
      } else {
        _super.apply(this, arguments);
      }
    }
  }

  Assertion.overwriteMethod('min', min);
  Assertion.overwriteMethod('least', min);

  function max (_super) {
    return function (n) {
      if (this._obj.__isSpy) {
        new Assertion(this._obj).to.be.spy;

        this.assert(
            this._obj.calls.length <=  n
          , 'expected ' + this._obj + ' to have been called at most #{exp} times but got #{act}'
          , 'expected ' + this._obj + ' to have been called more than #{exp} times but got #{act}'
          , n
          , this._obj.calls.length
        );
      } else {
        _super.apply(this, arguments);
      }
    }
  }

  Assertion.overwriteMethod('max', max);
  Assertion.overwriteMethod('most', max);
}