/**
 * Minimal Unit Test Harness
 *
 * Licensed under the MIT License
 *
 * Copyright(c) 2014, Google Inc.
 */
var muther = {
  assert(cond, err) { if (!cond) { throw err || 'Undefined error'; } },
  assertEquals(a, b, err) { muther.assert(a === b, err || (a + '!=' + b)); },
  assertThrows(fn, err) {
    let threw = false;
    try { fn(); } catch (e) { threw = true; }
    muther.assert(threw, err || 'Code did not throw');
  },

  $(id) {
    let el = document.querySelector('#' + id);
    if (!el) {
      el = document.createElement('div');
      el.id = id;
      document.body.appendChild(el);
    }
    return el;
  },

  set_(id, style, innerHTML) {
    muther.$(id).setAttribute('style', style);
    muther.$(id).innerHTML = innerHTML;
  },

  go(spec) {
    let prevResult = Promise.resolve(true);
    for (let testName in spec['tests']) {
      muther.set_(testName, 'color:#F90', 'RUNNING: ' + testName);
      try {
        prevResult = prevResult.then(() => {
          if (spec['setUp']) spec['setUp']();
          const thisResult = spec['tests'][testName]() || Promise.resolve(true);
          return thisResult.then(() => {
            if (spec['tearDown']) spec['tearDown']();
            muther.set_(testName, 'color:#090', 'PASS: ' + testName);
          });
        }).catch(err => muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err));
      } catch (err) {
        muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err);
      }
    }
  },  
};