mm
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    3.2.0 • Public • Published

    mm

    NPM version build status Test coverage David deps npm download

    An simple but flexible mock(or say stub) package, mock mate.

    mm@2 only support node v4.0+.

    Install

    $ npm install mm --save-dev

    Usage

    var mm = require('mm');
    var fs = require('fs');
     
    mm(fs, 'readFileSync', function(filename) {
      return filename + ' content';
    });
     
    console.log(fs.readFileSync('《九评 Java》'));
    // => 《九评 Java》 content
     
    mm.restore();
     
    console.log(fs.readFileSync('《九评 Java》'));
    // => throw `Error: ENOENT, no such file or directory '《九评 Java》`

    Support spy

    If mocked property is a function, it will be spied, every time it called, mm will modify .called, .calledArguments and .lastCalledArguments. For example:

    const target = {
      async add(a, b) {
        return a + b;
      },
    };
     
    mm.data(target, 'add', 3);
     
    assert.equal(await target.add(1, 1), 3);
    assert.equal(target.add.called, 1);
    assert.deepEqual(target.add.calledArguments, [[ 1, 1 ]]);
    assert.deepEqual(target.add.lastCalledArguments, [ 1, 1 ]);
     
    assert.equal(await target.add(2, 2), 3);
    assert.equal(target.add.called, 2);
    assert.deepEqual(target.add.calledArguments, [[ 1, 1 ], [ 2, 2 ]]);
    assert.deepEqual(target.add.lastCalledArguments, [ 2, 2 ]);

    If you only need spy and don't need mock, you can use mm.spy method directly:

    const target = {
      async add(a, b) {
        await this.foo();
        return a + b;
      },
      async foo() { /* */ },
    };
     
    mm.spy(target, 'add');
    assert.equal(await target.add(1, 1), 2);
    assert.equal(target.add.called, 1);
    assert.deepEqual(target.add.calledArguments, [[ 1, 1 ]]);
    assert.deepEqual(target.add.lastCalledArguments, [ 1, 1 ]);
     
    assert.equal(await target.add(2, 2), 4);
    assert.equal(target.add.called, 2);
    assert.deepEqual(target.add.calledArguments, [[ 1, 1 ], [ 2, 2 ]]);
    assert.deepEqual(target.add.lastCalledArguments, [ 2, 2 ]);

    Support generator function

    var foo = {
      get: function* () {
        return 1;
      }
    };
     
    mm.data(foo, 'get', 2);
    var data = yield* foo.get(); // data should return 2
     
    mm.error(foo, 'get', 'error boom');
    yield* foo.get(); // should throw error

    API

    .error(module, propertyName, errerMessage, errorProperties)

    var mm = require('mm');
    var fs = require('fs');
     
    mm.error(fs, 'readFile', 'mock fs.readFile return error');
     
    fs.readFile('/etc/hosts', 'utf8', function (err, content) {
      // err.name === 'MockError'
      // err.message === 'mock fs.readFile return error'
      console.log(err);
     
      mm.restore(); // remove all mock effects.
     
      fs.readFile('/etc/hosts', 'utf8', function (err, content) {
        console.log(err); // => null
        console.log(content); // => your hosts
      });
    });

    .errorOnce(module, propertyName, errerMessage, errorProperties)

    Just like mm.error(), but only mock error once.

    const mm = require('mm');
    const fs = require('fs');
     
    mm.errorOnce(fs, 'readFile', 'mock fs.readFile return error');
     
    fs.readFile('/etc/hosts', 'utf8', function (err, content) {
      // err.name === 'MockError'
      // err.message === 'mock fs.readFile return error'
      console.log(err);
     
      fs.readFile('/etc/hosts', 'utf8', function (err, content) {
        console.log(err); // => null
        console.log(content); // => your hosts
      });
    });

    .data(module, propertyName, secondCallbackArg)

    mm.data(fs, 'readFile', new Buffer('some content'));
     
    // equals
     
    fs.readFile = function (...args, callback) {
      callback(null, new Buffer('some content'))
    };

    .empty(module, propertyName)

    mm.empty(mysql, 'query');
     
    // equals
     
    mysql.query = function (...args, callback) {
      callback();
    }

    .datas(module, propertyName, argsArray)

    mm.datas(urllib, 'request', [new Buffer('data'), {headers: { foo: 'bar' }}]);
     
    // equals
     
    urllib.request = function (...args, callback) {
      callback(null, new Buffer('data'), {headers: { foo: 'bar' }});
    }

    .syncError(module, propertyName, errerMessage, errorProperties)

    var mm = require('mm');
    var fs = require('fs');
     
    mm.syncError(fs, 'readFileSync', 'mock fs.readFile return error', {code: 'ENOENT'});
     
    // equals
     
    fs.readFileSync = function (...args) {
      var err = new Error('mock fs.readFile return error');
      err.code = 'ENOENT';
      throw err;
    };
     

    .syncData(module, propertyName, value)

    mm.syncData(fs, 'readFileSync', new Buffer('some content'));
     
    // equals
     
    fs.readFileSync = function (...args) {
      return new Buffer('some content');
    };

    .syncEmpty

    mm.syncEmpty(fs, 'readFileSync');
     
    // equals
     
    fs.readFileSync = function (...args) {
      return;
    }

    .restore()

    // restore all mock properties
    mm.restore();

    .http.request(mockUrl, mockResData, mockResHeaders) and .https.request(mockUrl, mockResData, mockResHeaders)

    var mm = require('mm');
    var http = require('http');
     
    var mockURL = '/foo';
    var mockResData = 'mock data';
    var mockResHeaders = { server: 'mock server' };
    mm.http.request(mockURL, mockResData, mockResHeaders);
    mm.https.request(mockURL, mockResData, mockResHeaders);
     
    // http
    http.get({
      path: '/foo'
    }, function (res) {
      console.log(res.headers); // should be mock headers
      var body = '';
      res.on('data', function (chunk) {
        body += chunk.toString();
      });
      res.on('end', function () {
        console.log(body); // should equal 'mock data'
      });
    });
     
    // https
    https.get({
      path: '/foo'
    }, function (res) {
      console.log(res.headers); // should be mock headers
      var body = '';
      res.on('data', function (chunk) {
        body += chunk.toString();
      });
      res.on('end', function () {
        console.log(body); // should equal 'mock data'
      });
    });

    .http.requestError(mockUrl, reqError, resError) and .https.requestError(mockUrl, reqError, resError)

    var mm = require('mm');
    var http = require('http');
     
    var mockURL = '/foo';
    var reqError = null;
    var resError = 'mock res error';
    mm.http.requestError(mockURL, reqError, resError);
     
    var req = http.get({
      path: '/foo'
    }, function (res) {
      console.log(res.statusCode, res.headers); // 200 but never emit `end` event
      res.on('end', fucntion () {
        console.log('never show this message');
      });
    });
    req.on('error', function (err) {
      console.log(err); // should return mock err: err.name === 'MockHttpResponseError'
    });

    .classMethod(instance, method, mockMethod)

    class Foo {
      async fetch() {
        return 1;
      }
    }
     
    const foo = new Foo();
    const foo1 = new Foo();
     
    mm.classMethod(foo, 'fetch', async () => {
      return 3;
    });
    assert(await foo.fetch() === 3);
    assert(await foo1.fetch() === 3);

    License

    This software is licensed under the MIT License.
    
    Copyright (C) 2012 - 2014 fengmk2 <fengmk2@gmail.com>
    Copyright (C) 2015 - present node-modules
    
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
    

    Install

    npm i mm

    DownloadsWeekly Downloads

    31,486

    Version

    3.2.0

    License

    MIT

    Unpacked Size

    36.7 kB

    Total Files

    7

    Last publish

    Collaborators

    • atian25
    • dead_horse
    • fengmk2
    • popomore