Function customRunner

src/tests/frontend/runner.js:26–168

(runner)

  };

  const customRunner = (runner) => {
    const stats = {suites: 0, tests: 0, passes: 0, pending: 0, failures: 0};
    let level = 0;

    if (!runner) return;

    // AUTO-SCROLLING:

    // Mocha can start multiple suites before the first 'suite' event is emitted. This can break the
    // logic used to determine if the div is already scrolled to the bottom. If this is false,
    // auto-scrolling unconditionally scrolls to the bottom no matter how far up the div is
    // currently scrolled. If true, auto-scrolling only happens if the div is scrolled close to the
    // bottom.
    let manuallyScrolled = false;
    // The 'scroll' event is fired for manual scrolling as well as JavaScript-initiated scrolling.
    // This is incremented while auto-scrolling and decremented when done auto-scrolling. This is
    // used to ensure that auto-scrolling never sets manuallyScrolled to true.
    let autoScrolling = 0;

    // Auto-scroll the #mocha-report div to show the newly added test entry if it was previously
    // scrolled to the bottom.
    const autoscroll = (newElement) => {
      const mr = $('#mocha-report')[0];
      const scroll = !manuallyScrolled || (() => {
        const offsetTopAbs = newElement.getBoundingClientRect().top;
        const mrOffsetTopAbs = mr.getBoundingClientRect().top - mr.scrollTop;
        const offsetTop = offsetTopAbs - mrOffsetTopAbs;
        // Add some margin to cover rounding error and to make it easier to engage the auto-scroll.
        return offsetTop <= mr.clientHeight + mr.scrollTop + 5;
      })();
      if (!scroll) return;
      ++autoScrolling;
      mr.scrollTop = mr.scrollHeight;
      manuallyScrolled = false;
    };

    $('#mocha-report').on('scroll', () => {
      if (!autoScrolling) manuallyScrolled = true;
      else --autoScrolling;
    });

    runner.on('start', () => {
      stats.start = new Date();
    });

    runner.on('suite', (suite) => {
      if (suite.root) return;
      autoscroll($('#mocha-report .suite').last()[0]);
      stats.suites++;
      append(suite.title);
      level++;
    });

    runner.on('suite end', (suite) => {
      if (suite.root) return;
      level--;

      if (level === 0) {