b4dnewz/process-test

Easy way to test command line applications

process-test

Easy way to test command line applications

This project is mainly based on coffee but implemented in TypeScript with no dependencies.

Install

npm install @b4dnewz/process-test

Usage

You can use it in your tests with any framework to test your code execution:

import {fork, spawn} from "@b4dnewz/process-test"

// Spawn a nodejs process
it("will spawn node script", (done) => {
  fork("./test.js", ["foo", "bar"], {})
    .expect("stdout", /foo bar/)
    .expect("code", 0)
    .end(done);
})

// Spawn a system command
it("will spawn system command", (done) => {
  spawn("node", ["--version"], {})
    .expect("stdout", process.version)
    .expect("code", 0)
    .end(done);
})

File used in usage example test.js

#!/usr/bin/env node

const argv = process.argv.slice(2).join(" ")
process.stdout.write(argv);

API

fork

This method is used specifically to spawn new Node.js process using the given file path, arguments and options.

// fork(binPath)
fork("./test.js")

// fork(binPath, args)
fork("./test.js", ["--foo", "bar"])

// fork(binPath, args, options)
fork("./test.js", ["foo"], { env: {} })

spawn

This method spawns a new process using the given command, arguments and options.

// spawn(binPath)
spawn("node")

// spawn(binPath, args)
spawn("node", ["--version"])

// spawn(binPath, args, options)
spawn("ls", ["-l"], {
  cwd: "/home"
})

All the methods returns a test Process class which has the following method to interact with the process and the result:

expect(type, expectation)

This method is used to set an expectation of the process result.

spawn("node", ["--version"])
  .expect("stdout", new RegExp(process.version))
  .expect("code", 0);

notExpect(type, expectation)

This method is used to set an expectation of the process result.

spawn("node", ["--version"])
  .notExpect("code", 1);

---

License

MIT © Filippo Conti

process-test's Issues

Assertion errors are cathed from end callback

While using this package on tests I realized the assertion error raised from jest (in my case) was catched by the try/catch block where the end callback is called, more precisely from this code.

process-test/src/process.ts

Lines 292 to 296 in 542abd8

	if (this.endCb) {
	this.endCb(undefined, result);
	} else {
	this.emit("complete_success", result);
	}

Simply moving that part into a finally block is the solution.