const Mocha = require('mocha');

const { Writable } = require('stream');

const path = require('path');

const chalk = require('chalk');

// babel-register only looks for environment variables

process.env.BABEL_ENV = process.env.BABEL_ENV || 'test';

// use babel-register to compile files on the fly

// require('babel-register');

require("@babel/register");

require('babel-polyfill');

// require mocha setup files

require('../src/platform/testing/unit/mocha-setup.js');

require('../src/platform/testing/unit/enzyme-setup.js');

let showErrors = false;

// keys for current require.cache

const unwatchedModules = Object.keys(require.cache).map(file => file);

process.on('message', ({ tests, shouldShowErrors }) => {

showErrors = shouldShowErrors;

runMochaTests(tests).then(() => {

// create a list of src and test files required by mocha

const requiredFiles = Object.keys(require.cache).filter(

file =>

!unwatchedModules.includes(file) && !file.includes('node_modules'),

);

// send list of imported files and unit tests for each src file to the runner

process.send({

requiredFiles,

unitTestsForSrc: getUnitTestsForSrc(requiredFiles),

});

});

});

async function runMochaTests(files) {

// show the file names if fewer than ten

if (files.length < 10) {

files.forEach(file => {

let fileParts = path.basename(file).split('.');

console.log(

`${chalk.cyan(fileParts.shift())}.${chalk.blue(fileParts.join('.'))}`,

);

});

}

console.log(' ');

// keep errors from polluting the reporter by redirecting the error stream

let errorStream;

if (!showErrors) {

errorStream = new Writable({

write(chunk, encoding, callback) {

callback();

},

});

process.stderr.write = errorStream;

}

mocha = new Mocha();

mocha.reporter('nyan');

// sets up globals

mocha.addFile('./src/platform/testing/unit/helpers.js');

files.forEach(file => mocha.addFile(file));

return new Promise((fulfill, reject) => {

console.log(chalk.green('Starting mocha (this can take a few seconds)...'));

mocha.run().once('end', function() {

// reattach error stream

fulfill();

});

}).catch(error => {

console.log(error);

process.send({

error,

});

});

}

function getUnitTestsForSrc(requiredFiles) {

return (

requiredFiles

// only use files in test directory

.filter(file => file.includes('test'))

// iterate over each test file

.reduce((acc, testFile) => {

// get the test files require.cache

const requiredSourceFiles = require.cache[testFile].children // children is an array of modules the test file imports

.forEach(childModule => {

// filter anything that isn't in the src directory

if (!childModule.id.includes('src')) {

return;

}

// add the file path as a key to the accumulator

// add the test file to the tests array

if (acc[childModule.id]) {

acc[childModule.id].push(testFile);

} else {

acc[childModule.id] = [testFile];

}

});

return acc;

}, {})

);

}

// ensures errors that blow up test watcher make it to console reporter

process.on('uncaughtException', function(err) {

console.error(err && err.stack ? err.stack : err);

});