runner.js

#!/usr/bin/env node
/* eslint-disable import/no-dynamic-require,global-require,no-return-assign */

const { resolve, join } = require('path');
const parseOpts = require('minimist');
const md5File = require('md5-file');
const fs = require('fs-extra');
const dependencyTree = require('dependency-tree');
const _ = require('lodash');
const tape = require('tape');

const cwd = process.cwd();
const cachePath = filename => resolve(cwd, 'tmp', 'client-tests', filename);
const opts = parseOpts(process.argv.slice(2), {
  alias: { r: 'require' },
  string: 'require',
  default: { r: [] },
});

const dependencyList = filename =>
  dependencyTree.toList({ filename, directory: cwd });

const targetFiles = _(opts._)
  .map(dependencyList)
  .flatten()
  .map(name => name.replace(join(cwd, '/'), ''))
  .value();

  // Gets all helpful information for files
const fileStats = targetFiles.map((filename) => {
  const newHash = md5File.sync(filename);
  const filepath = cachePath(filename);

  let oldHash = '';
  try {
    oldHash = fs.readFileSync(filepath).toString();
  } catch (e) {
    /* Cache file does not yet exist */
  }

  return {
    changed: newHash !== oldHash,
    hash: newHash,
    path: resolve(cwd, filename),
    name: filename,
  };
});

// Gets all changed files
const changedFiles = fileStats
  .filter(({ changed }) => changed)
  .map((file) => {
    const depTree = dependencyTree.toList({
      filename: file.name,
      directory: cwd,
    });

    return Object.assign({}, file, { depTree });
  });

// Gets all test files that have changed or have children that have changed
const testFileStats = changedFiles
  .map((file) => {
    if (file.name.endsWith('.test.es6')) {
      return [file];
    }

    const moreFiles = fileStats
      .filter(({ name }) => name.endsWith('.test.es6'))
      .filter((_file) => {
        const depTree = dependencyTree.toList({
          filename: _file.name,
          directory: cwd,
        });

        return depTree.indexOf(file.path) > -1;
      });

    return moreFiles;
  })
  .filter(file => file.length !== 0);

// Gets the name of the file
const files = _.flatten(testFileStats).map(({ name }) => name);

if (files.length === 0) {
  console.log('\n✅  No files have changed \n');
  process.exit(0);
}

// Test running set up. Putting these down here for performance reasons.
require('babel-register');
require('./setup.js');

// Set up output to stdout
const outputStream = tape.createStream();
outputStream.pipe(process.stdout);

// Track failed tests and delete their cache
let outputString = '';
outputStream.on('data', data => outputString += data.toString());
outputStream.on('end', () => {
  _(outputString)
    .split('\n')
    .filter(str => str.indexOf('.test.es6:') > -1)
    .map(str => str.trim())
    .map((str) => {
      const index = str.indexOf('app/client');
      return str.substr(index).split(':')[0];
    })
    .uniq()
      // Invalidate failed files's cache
    .forEach(filename => fs.removeSync(cachePath(filename)));
});

files.forEach(file => require(resolve(cwd, file)));

// Write changed files's cache
changedFiles.forEach((stat) => {
  fs.outputFileSync(resolve(cwd, 'tmp', 'client-tests', stat.name), stat.hash);
});