gallinago

Gallinago is designed to assist with the running and testing of NodeJS CLIs and binaries in a simple and controlled way. It is best used in combination with fixtures and pre-scaffolded directories such that you can reproduce the various configuration and folder structures your CLI may need to support for its users and then validate the output. Perfect for testing!

Overview

Often times while creating CLIs, it can be helpful to test the final output given the various configurations of a CLI. Running a CLI using config files and user files will all likely (and hopefully) result in idempotent output that can be validated over and over. With a testing framework like mocha, you could use Gallinago to run your CLI and verify that output to validate things like:

• Were the right files created?
• Was the output what I expected?
• Were too many files created?
• Does it work for configuration A?
• Does it work for configuration B?
• etc

Install

Use npm or your favorite package manager to install Gallinago as a (dev) dependency.

$ npm install gallinago --dev

Usage

To use Gallinago, you will just need two things

1. An absolute path to your CLI
2. An absolute path to the directory you want Gallinago to run your CLI in

import path from 'path';
import { Runner } = from 'gallinago';
import { fileURLToPath, URL } from 'url';

const runner = new Runner();

const cliPath = fileURLToPath(new URL('./path/to/your/cli.js', import.meta.url)); // required
const buildDir = fileURLToPath(new URL('./build', import.meta.url)); // required

// this will also create the directory as well
await runner.setup(buildDir);

// runs your CLI
// use the second param to pass any args
await runner.runCommand(cliPath);

// teardown buildDir
await runner.teardown();

See our tests to see Gallinago in action!

API

Runner

The Runner constructor returns a new instance of Runner.

import { Runner } from 'gallinago';

const runner = new Runner();  // pass true to the constructor to enable stdout

Options

Runner takes two boolean flags (true|false)

• Standard Out - pass true to have the Runner log to stdout
• Forward Parent Args - pass true and any node flags passed to the parent process will be made available to the child process

Runner.setup (required)

Runner.setup initializes a directory for your CLI to be run in. Returns a Promise.

await runner.setup(__dirname);

Optionally, you can provide "setup" files if you want to copy additional files into the target directory, say from node_modules or a fixtures folder. You can provide these files as an array of objects.

• source: path of the file to copy
• destination: path of where to copy the file to

A third options object can be provided with the following supported options

• create - automatically create the directory provided in the first param (default is true)

await runner.setup(__dirname, [{
  source: path.join(process.cwd(), 'node_modules/@webcomponents/webcomponentsjs/webcomponents-bundle.js'),
  destination: path.join(__dirname, 'build', 'webcomponents-bundle.js')
}], {
  create: true
});

Runner.runCommand

Runner.runCommand runs the script provided to Gallinago against the directory provided in Runner.setup. Use the second param to pass any args to your CLI. Returns a Promise.

await runner.runCommand(
  '/path/to/cli.js',
  '--version'
);

You can also provide an array as the second param to support forwarding individual args, useful when using projects like commander:

await runner.runCommand(
  '/path/to/cli.js',
  ["--name", "my-app"]
);

Options

runCommand additionally takes an options object as the third param. With it you can further customize the runner:

runner.runCommand(
  '/path/to/cli.js',
  '--version',
  { onStdOut: (text) => console.log(text) }
);

onStdOut

This is a callback function that is invoked with a string each time the child process writes to std out. Defaults to null. In conjunction with stopCommand, this can be useful to listen for when a long running command is "ready", like waiting for a web server to start.

before(async function () {
  await runner.setup(outputPath);

  await new Promise((resolve, reject) => {
    runner.runCommand(
      '/path/to/cli.js',
      "develop",
      { onStdOut: (message) => {
        if (message.includes(`Started local development server at http://localhost:8080`)) {
          resolve();
        }
      }}
    ).catch(reject)
  });
});

Runner.teardown

Runner.teardown deletes any setupFiles provided in Runner.setup. Returns a Promise.

await runner.teardown();

You can pass additional files or directories to teardown to have gallinago delete those too.

await runner.teardown([
  path.join(__dirname, 'build'),
  path.join(__dirname, 'fixtures'),
  .
  .
  .
]);

Runner.stopCommand

In certain circumstances, the command (process) you are running may do a couple things:

• Spawn its own child process(es), which is independent of the lifecycle of its parent process
• Not close itself (and thus never resolve() the on.close event callback)

This isn't an issue per se, but if the (child) process doesn't stop, it will prevent the current (parent) process from completing. The most common case for something like this to happen is when starting a (web) server. Servers don't usually stop unless told to, usually by killing their process manually using something like PM2, or if in a shell, using CTR+C on the keyboard.

To support this in Gallinago, you can use Runner.stopCommand to kill any and all processes associated with your runCommand.

await runner.stopCommand();

Note: When used with something like mocha, you'll need to use a setTimeout to work around the hung process and still advance the parent Mocha process. See our spec for this test case for a complete example.