testarmada-magellan-mocha-plugin/lib/test_capture.js

var fs = require('fs');

/**
 * Recursive function, takes a mocha test suite and returns a flattened list of
 * test found within
 */
function getTests(suite) {
  var tests = [];

  suite.tests.forEach(function(t) {
    tests.push({
      file: t.file,
      title: t.title,
      fullTitle: t.fullTitle(),
      pending: t.pending
    });
  });

  suite.suites.forEach(function(s) {
    tests = tests.concat(getTests(s));
  });

  return tests;
}

/**
 * Used as a mocha repoter for the test capturing phase
 */
module.exports = function(runner, options) {
  var outputPath = process.env.MOCHA_CAPTURE_PATH;
  if (!outputPath) {
    throw new Error('Environment variable MOCHA_CAPTURE_PATH must be defined');
  }

  // capture but do not run tests
  runner.run = function(done) {
    done();
  }

  // traverse suite structure and flattened list of tests
  var tests = getTests(runner.suite);

  // process .only greps
  if (options.grep) {
    tests = tests.filter(function(t) {
      return t.fullTitle.match(options.grep);
    });
  }

  fs.writeFileSync(process.env.MOCHA_CAPTURE_PATH, JSON.stringify(tests));
};