bdd-stdin

Utility for easily mocking user responses for BDD unit tests that ask user a question.

I needed something to help unit testing CLI apps.

npm install bdd-stdin --save-save

typing text

var ask = require('./ask');
// ask is promise-returning stdin question
var bddStdin = require('bdd-stdin');
describe('ask', function () {
  it('asks one question', function () {
    bddStdin('answer');
    return ask('type "answer"')
      .then(function (response) {
        console.assert(response === 'answer');
      });
  });
});

You can provide multiple answers to be delivered in turns

var ask = require('./ask');
var bddStdin = require('bdd-stdin');
describe('ask', function () {
  it('asks one question', function () {
    bddStdin('one', 'two');
    return ask('type "one"')
      .then(function (response) {
        console.assert(response === 'one');
        return ask('type "two"');
      })
      .then(function (response) {
        console.assert(response === 'two');
      });
  });
});

You can even provide answers before each question individually

it('asks three questions separately', function () {
  bddStdin('one');
  return ask('question 1')
    .then(function (response) {
      console.assert(response === 'one', 'received response ' + response);
      bddStdin('two');
      return ask('question 2');
    })
    .then(function (response) {
      console.assert(response === 'two', 'received response ' + response);
      bddStdin('three');
      return ask('question 3');
    }).then(function (response) {
      console.assert(response === 'three', 'received response ' + response);
    });
});

selecting choice using up / down keys

If you use a 3rd party library, like inquirer you need to select the right choice using up / down keys. The bddStdin object has object property keys with up, down, left and right codes.

For example the follwing code

var inquirer = require('inquirer');
var question = {
  type: 'list',
  name: 'choice',
  message: 'pick three',
  choices: ['one', 'two', 'three']
};
inquirer.prompt([question], function (answers) {
  console.log('user picked', answers.choice);
});

presents the user with the following prompt:

? pick three: (Use arrow keys)
❯ one 
  two 
  three

We can provide mock answer in our unit tests

var bddStdin = require('bdd-stdin');
it('selects the third choice', function (done) {
  bddStdin(bddStdin.keys.down, bddStdin.keys.down, '\n');
  var question = {
    type: 'list',
    name: 'choice',
    message: 'pick three',
    choices: ['one', 'two', 'three']
  };
  inquirer.prompt([question], function (answers) {
    console.assert(response === 'three', 'received response ' + response);
    done();
  });
});

Small print

Author: Gleb Bahmutov © 2015

• @bahmutov
• glebbahmutov.com
• blog

License: MIT - do anything with the code, but don't blame me if it does not work.

Spread the word: tweet, star on github, etc.

Support: if you find any problems with this module, email / tweet / open issue on Github

MIT License

Copyright (c) 2015 Gleb Bahmutov

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.