Nomadic People Migration

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    Visual Studio Code Wallaby.js

    Hello masters,

    My name is mockto.

    I'm the main automaton and you guide to the mocktomata system.

    In a nut shell, mocktomata can save the behavior of your code, and simulate it at a later time.

    We can isolate your code from the changes and uncertainty of the outside world. And we can connect your code back to it by a flip of a switch.

    Most of the time, we are summoned by masters when they are writing tests.

    Writing tests with us has several benefits over traditional tests.

    Traditionally, masters write different type of tests: unit tests, integration tests, and acceptance tests etc, to verify the system is working correctly.

    This approach has several drawbacks:

    • There are many duplications and overlaps between different type of tests.
    • Acceptance tests cannot run during build time.
    • Acceptance tests is slow and take a long time to complete.
    • Acceptance tests can fail when the external systems are unstable or change without notice.
    • Unit tests and integration tests give a false impression that the system is working while in reality the external system does not behave as expected causing the system to fail.
    • It is very expensive to setup and teardown environment for acceptance tests, especially when there are many environment variations and application states that are difficult to reach.

    Utilizing us can mitigate most of these drawbacks.

    Besides writing tests, you can also deploy us in production code, which you can do some very advance stuff

    So, welcome to mocktomata, Me and other automata at your service.


    npm install --dev mocktomata
    // or
    yarn add --dev mocktomata

    When using mocktomata, we will record the behavior as SpecRecord. They are saved under the .mocktomata folder at the root of your project. Please check in that folder into your source control.


    My name is mockto.

    I am an automaton specialized in writing tests. You can refer to me as mt.

    Here is an example on how to work with the axios library:

    import axios from 'axios'
    import { mockto } from 'mocktomata'
    // `mockto(specName, handler)`
    // `specName` must be unqique within the test file.
    // so you need to be careful when using grouping mechanics such as `describe()`
    mockto('get friends', (title, spec) => {
      // `title` is the same as `specName`.
      // It is provided to use as the test title,
      // so you don't need to repeat the message manually.
      test(title, async () => {
        // `spec(subject)` creates a substitute to be used in place of the `subject`
        const s = await spec(axios)
        const friends = await getFriends(s, 'miku')
        expect( =>['luka', 'rumi', 'len', 'ren'])
        // indicates the spec is completed.
        await spec.done()

    That is typically all you need to do. Internally, I'll record the behavior and replay it as needed.

    Of course, I can do a lot more. Please check out my user manual for more information.


    Hi, I'm komondor.

    I used to be a guard dog.

    But as time passes, I become a part of the mocktomata family as an automaton. Masters can also call me kd if you like.

    While mockto is specialized for testing, I'm more general purposed and versatile.

    Here is how masters dispatch me in the same axios example:

    import axios from 'axios'
    import { komondor } from 'mocktomata'
    test('get friends', async () => {
      const spec = komondor('get friends')
      const s = await spec(axios)
        const friends = await getFriends(s, 'miku')
        expect( =>['luka', 'rumi', 'len', 'ren'])
      await spec.done()

    If you want to use mocktomata in production for advance usage, I'm the one you can depend on.

    To know more about me, you can check out my raising guide user manual.


    My name is incubator, master.

    I am specialized in helping masters to create plugins.

    The way I work is very similar to mockto:

    import { incubator } from 'mocktomata'
    import { activate } from './your-plugin'
    incubator.config({ plugins: [['your-plugin', activate]] })
    incubator('some test', (title, spec) => {
      test(title, async () => {
        const s = await spec(YourPluginSubject)
        const actual = specificUsage(s)
        await spec.done()

    The difference is I will go through the lifecycle of SpecRecord by running the test twice: once as ${specName}: save and once as ${specName}: simulate.

    Also, the SpecRecord is stored in memory and not written to file.

    Please checout my responsibility list for more information.


    Hi, it's mockto again.

    By default, mocktomata) works out-of-the-box without any configuration. It should be able to cover most of the use cases for testing.

    But you can configure mocktomata) to do more things such as using additional plugins, and changing the behavior of the auto mode.

    Did I mentioned that you can change your unit tests to acceptance tests by a flip of a switch?

    To learn more, please chect out the configuration manual.

    Wallaby config

    Since mocktomata will write files to the file system, if you use wallaby you need configure it as follow so that the changed files will be written correctly:

    module.exports = () => {
      return {
        'files': [
          // load spec records
          { pattern: '.mocktomata/**/*', instrument: false },
        setup(wallaby) {
          const fs = require('fs');
          if (fs.patched) return;
          const path = require('path');
          const writeFile = fs.writeFileSync;
          fs.writeFileSync = function(file, content) {
            if (/.mocktomata/.test(file)) {
              writeFile(path.join(wallaby.localProjectDir, file.replace(wallaby.projectCacheDir, '')), content);
            return writeFile.apply(this, arguments);
          const mkdirSync = fs.mkdirSync;
          fs.mkdirSync = function (dir, mode) {
            if (/.mocktomata/.test(dir)) {
              mkdirSync(path.join(wallaby.localProjectDir, dir.replace(wallaby.projectCacheDir, '')), mode);
            return mkdirSync.apply(this, arguments);
          fs.patched = true;


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