fork.js

/*
Based on https://github.com/avajs/ava/blob/033d4dcdcbdadbf665c740ff450c2a775a8373dc/lib/fork.js

The MIT License (MIT)

Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)

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.
*/

'use strict';
const childProcess = require('child_process');
const path = require('path');
const fs = require('fs');
const Promise = require('bluebird');
const AvaError = require('ava/lib/ava-error');

if (fs.realpathSync(__filename) !== __filename) {
	console.warn('WARNING: `npm link ava` and the `--preserve-symlink` flag are incompatible. We have detected that AVA is linked via `npm link`, and that you are using either an early version of Node 6, or the `--preserve-symlink` flag. This breaks AVA. You should upgrade to Node 6.2.0+, avoid the `--preserve-symlink` flag, or avoid using `npm link ava`.');
}

let env = process.env;

// Ensure NODE_PATH paths are absolute
if (env.NODE_PATH) {
	env = Object.assign({}, env);

	env.NODE_PATH = env.NODE_PATH
		.split(path.delimiter)
		.map(x => path.resolve(x))
		.join(path.delimiter);
}

// In case the test file imports a different AVA install,
// the presence of this variable allows it to require this one instead
env.AVA_PATH = path.resolve(require.resolve('ava'), '..');

module.exports = (file, opts, execArgv) => {
	opts = Object.assign({
		file,
		baseDir: process.cwd(),
		tty: process.stdout.isTTY ? {
			columns: process.stdout.columns,
			rows: process.stdout.rows
		} : false
	}, opts);

	const ps = childProcess.spawn(require('electron'), [require.resolve('./main-process/test-starter'), JSON.stringify(opts)], {
		stdio: [null, null, null, 'ipc'],
		cwd: opts.pkgDir,
		silent: true,
		env,
		execArgv: execArgv || process.execArgv
	});

	const relFile = path.relative('.', file);

	let exiting = false;
	const send = (name, data) => {
		if (!exiting) {
			// This seems to trigger a Node bug which kills the AVA master process, at
			// least while running AVA's tests. See
			// <https://github.com/novemberborn/_ava-tap-crash> for more details.
			ps.send({
				name: `ava-${name}`,
				data,
				ava: true
			});
		}
	};

	const testResults = [];
	let results;

	const promise = new Promise((resolve, reject) => {
		ps.on('error', reject);

		// Emit `test` and `stats` events
		ps.on('message', event => {
			if (!event.ava) {
				return;
			}

			event.name = event.name.replace(/^ava-/, '');
			event.data.file = relFile;

			ps.emit(event.name, event.data);
		});

		ps.on('test', props => {
			testResults.push(props);
		});

		ps.on('results', data => {
			results = data;
			data.tests = testResults;
			send('teardown');
		});

		ps.on('exit', (code, signal) => {
			if (code > 0) {
				return reject(new AvaError(`${relFile} exited with a non-zero exit code: ${code}`));
			}

			if (code === null && signal) {
				return reject(new AvaError(`${relFile} exited due to ${signal}`));
			}

			if (results) {
				resolve(results);
			} else {
				reject(new AvaError(`Test results were not received from ${relFile}`));
			}
		});

		ps.on('no-tests', data => {
			send('teardown');

			let message = `No tests found in ${relFile}`;

			if (!data.avaRequired) {
				message += ', make sure to import "ava" at the top of your test file';
			}

			reject(new AvaError(message));
		});
	});

	// Teardown finished, now exit
	ps.on('teardown', () => {
		send('exit');
		exiting = true;
	});

	// Uncaught exception in fork, need to exit
	ps.on('uncaughtException', () => {
		send('teardown');
	});

	ps.stdout.on('data', data => {
		ps.emit('stdout', data);
	});

	ps.stderr.on('data', data => {
		ps.emit('stderr', data);
	});

	promise.on = function () {
		ps.on.apply(ps, arguments);
		return promise;
	};

	promise.send = (name, data) => {
		send(name, data);
		return promise;
	};

	promise.exit = () => {
		send('init-exit');
		return promise;
	};

	// Send 'run' event only when fork is listening for it
	let isReady = false;

	ps.on('stats', () => {
		isReady = true;
	});

	promise.run = options => {
		if (isReady) {
			send('run', options);
			return promise;
		}

		ps.on('stats', () => {
			send('run', options);
		});

		return promise;
	};

	return promise;
};