Coffee NPM | npm.io

Coffee

Test command line on Node.js.

Install

$ npm i coffee --save-dev

Usage

Coffee is useful for test command line in test frammework (like Mocha).

Fork

You can use fork for spawning Node processes.

const coffee = require('coffee');

describe('cli', () => {
  it('should fork node cli', () => {
    return coffee.fork('/path/to/file.js')
    .expect('stdout', '12\n')
    .expect('stderr', /34/)
    .expect('code', 0)
    .end();
  });
});

In file.js

console.log(12);
console.error(34);

You can pass args and opts to child_process fork.

coffee.fork('/path/to/file.js', [ 'args' ], { execArgv: [ '--inspect' ]})
  .expect('stdout', '12\n')
  .expect('stderr', '34\n')
  .expect('code', 0)
  .end();

And more:

coffee.fork('/path/to/file.js')
  // print origin stdio
  .debug()

  // inject a script
  .beforeScript(mockScript)

  // interact with prompt
  .waitForPrompt()
  .write('tz\n')

  // string strict equals
  .expect('stdout', 'abcdefg')
  // regex
  .expect('stdout', /^abc/)
  // multiple
  .expect('stdout', [ 'abcdefg', /abc/ ])
  .expect('code', 0)
  .end();

see the API chapter below for more details.

Spawn

You can also use spawn for spawning normal shell scripts.

coffee.spawn('cat')
  .write('1')
  .write('2')
  .expect('stdout', '12')
  .expect('code', 0)
  .end();

Rule

code

Check the exit code.

coffee.fork('/path/to/file.js', [ 'args' ])
  .expect('code', 0)
  // .expect('code', 1)
  .end();

stdout / stderr

Check the stdout and stderr.

coffee.fork('/path/to/file.js', [ 'args' ])
  .expect('stdout', '12\n')
  .expect('stderr', '34\n')
  .expect('code', 0)
  .end();

custom

Support custom rules, see test/fixtures/extendable for more details.

const { Coffee, Rule } = require('coffee');

class FileRule extends Rule {
  constructor(opts) {
    super(opts);
    // `args` is which pass to `expect(type, ...args)`, `expected` is the first args.
    const { args, expected } = opts;
  }

  assert(actual, expected, message) {
    // do sth
    return super.assert(fs.existsSync(expected), true, `should exists file ${expected}`);
  }
}

class MyCoffee extends Coffee {
  constructor(...args) {
    super(...args);
    this.setRule('file', FileRule);
  }

  static fork(modulePath, args, opt) {
    return new MyCoffee({
      method: 'fork',
      cmd: modulePath,
      args,
      opt,
    });
  }
}

Usage:

// test/custom.test.js
const coffee = require('MyCoffee');
coffee.fork('/path/to/file.js', [ 'args' ])
  .expect('file', `${root}/README.md`);
  .notExpect('file', `${root}/not-exist`);

Support multiple process coverage with nyc

Recommend to use nyc for coverage, you can use any test frammework supported by nyc.

API

coffee.spawn

Run command using child_process.spawn, then return Coffee instance.

Arguments see child_process.spawn

coffee.fork

Run command using child_process.fork, then return Coffee instance.

Arguments see child_process.fork

coffee.Coffee

Assertion object

coffee.expect(type, ...args)

Assert type with expected value, expected value can be string, regular expression, and array.

coffee.spawn('echo', [ 'abcdefg' ])
  .expect('stdout', 'abcdefg')
  .expect('stdout', /^abc/)
  .expect('stdout', [ 'abcdefg', /abc/ ])
  .end();

Accept type: stdout / stderr / code / error, see built-in rules description above.

coffee.notExpect(type, ...args)

The opposite assertion of expect.

coffee.includes(type, ...args)

Assert type with expected string value, expected value should be string only.

coffee.spawn('echo', [ 'abcdefg' ])
  .includes('stdout', 'abc')
  .expect('stdout', [ 'abc', 'efg' ])
  .end();

Accept type: stdout / stderr, see built-in rules description above.

coffee.notIncludes(type, ...args)

The opposite assertion of includes.

coffee.write(data)

Write data to stdin.

coffee.fork(path.join(fixtures, 'stdin.js'))
  .write('1\n')
  .write('2')
  .expect('stdout', '1\n2')
  .end();

coffee.writeKey(...args)

Write special key sequence to stdin, support UP / DOWN / LEFT / RIGHT / ENTER / SPACE.

All args will join as one key.

coffee.fork(path.join(fixtures, 'stdin.js'))
  .writeKey('1', 'ENTER', '2')
  .expect('stdout', '1\n2')
  .end();

coffee.waitForPrompt(bool)

If you set false, coffee will write stdin immediately, otherwise will wait for prompt message.

coffee.fork('/path/to/cli', [ 'abcdefg' ])
  .waitForPrompt()
  .write('tz\n')
  // choose the second item
  .writeKey('DOWN', 'DOWN', 'ENTER');
  .end(done);

cli process should emit prompt message:

Or use coffee.on('stdout', callback) instead, see docs below.

const readline = require('readline');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

function ask(q, callback) {
  process.send({ type: 'prompt' });
  rl.question(q, callback);
}

ask('What\'s your name? ', answer => {
  console.log(`hi, ${answer}`);
  ask('How many coffee do you want? ', answer => {
    console.log(`here is your ${answer} coffee`);
    rl.close();
  });
});

coffee.end(callback)

Callback will be called after completing the assertion, the first argument is Error if throw exception.

coffee.fork('path/to/cli')
  .expect('stdout', 'abcdefg')
  .end(done);

// recommended to left undefind and use promise style.
const { stdout, stderr, code } = await coffee.fork('path/to/cli').end();
assert(stdout.includes(abcdefg));

coffee.on(event, callback)

Emit stdout/stderr event.

use for kill long-run process:

coffee.fork('path/to/cli')
  .on('stdout', (buf, { proc }) => {
    if (buf.includes('egg-ready')) {
      proc.exitCode = 0;
      proc.kill();
    }
  })
  .expect('stdout', 'egg-ready')
  .end(done);

use for prompt:

// do not call `waitForPrompt` / `write` / `writeKey`
coffee.fork('path/to/cli')
  .on('stdout', (buf, { proc }) => {
    if (buf.includes('Your Name: ')) {
      proc.stdin.write('TZ\n');
    }
  })
  .expect('stdout', 'Your Name: TZ\n')
  .end(done);