How to use the @xviz/io.XVIZJSONProvider function in @xviz/io

test('XVIZJSONProvider#default-ctor init', async t => {
  // Ensure no parameter ctor
  const provider = new XVIZJSONProvider({source});
  await provider.init();
  t.ok(provider.valid(), 'Provider is valid');
  t.end();
});

test('XVIZJSONProvider#getMessageIterator()', async t => {
  const provider = new XVIZJSONProvider({source});
  await provider.init();
  t.ok(provider.valid(), 'Provider is valid');

  // Default to start/end of index file
  let iterator = provider.getMessageIterator();
  t.equals(iterator.start, 0, 'iterator w/o time starts is 0');
  t.equals(iterator.end, 1, 'iterator w/o time is 1');
  t.equals(iterator.current, 0, 'iterator w/o time current is 0');

  // Clamp to start/end of data
  iterator = provider.getMessageIterator({startTime: 1000, endTime: 1012});
  t.equals(iterator.start, 0, 'iterator start clamped to beginning');
  t.equals(iterator.end, 1, 'iterator end clamped to end');
  t.equals(iterator.current, 0, 'iterator current is 0');

  // Exact start/end of data

test('XVIZJSONProvider#message iteration', async t => {
  const provider = new XVIZJSONProvider({source});
  await provider.init();
  t.ok(provider.valid(), 'Provider is valid');

  const iterator = provider.getMessageIterator({startTime: 1000.5, endTime: 1010.5});

  const testMessage = async timestamp => {
    t.ok(iterator.valid());

    const message = await provider.xvizMessage(iterator);
    t.ok(message, 'message data is present');

    const messageData = message.message().data;
    t.equals(messageData.updates[0].timestamp, timestamp, 'First message matches expected value');
  };

  testMessage(1000.5);