@scalvert/bin-tester NPM

@scalvert/bin-tester

Provides a test harness for node CLIs that allow you to run tests against a real project.

Install

npm add @scalvert/bin-tester --save-dev

# or

yarn add @scalvert/bin-tester --dev

Usage

@scalvert/bin-tester uses two libraries to provide the test harness:

fixturify-project: Allows you to dynamically create test fixtures using real directories and files in a tmp directory
execa: A better replacement for child_process.exec

It combines the above and provides an API for running a binary with a set of arguments against a real project structure, thus mimicking testing a real environment.

import { createBinTester } from '@scalvert/bin-tester';

describe('Some tests', () => {
  let project;
  let { setupProject, teardownProject, runBin } = createBinTester({
    binPath: 'node_modules/.bin/someBin',
    staticArgs: ['--some-arg'], // pass some args to the bin that will be used for each invocation
  });

  beforeEach(() => {
    project = await setupProject();
  });

  afterEach(() => {
    await teardownProject();
  });

  // Run the bin and do something with the result
  test('a test', async () => {
    const result = await runBin();

    expect(result.stdout).toBe('Did some stuff');
  });

  test('another test', async () => {
    // Write a file with contents to the tmp directory
    await project.writeDirJSON({
      'some/file.txt': 'some content',
    });

    // pass some args to the bin that will be used for only this invocation
    const result = await runBin('--path', 'some/file.txt');

    expect(result.stdout).toBe('Read "some/file.txt"');
  });
});

API

Classes

Functions

BinTesterProject

Kind: global class

BinTesterProject
- new BinTesterProject(name, version, cb)
- .gitInit() ⇒ *
- .chdir()
- .dispose() ⇒ void

new BinTesterProject(name, version, cb)

Param	Type	Default	Description
name	string	"fake-project"	The name of the project. Used within the package.json as the name property.
version	string		The version of the project. Used within the package.json as the version property.
cb	function		An optional callback for additional setup steps after the project is constructed.