test rethinkdb query

test_query.js

const query = () => r.db('dataDb')
  .table('trackedUsers')
  .filter({ appId })
  .concatMap(user => r.db('dataDb').table('alive')
    .getAll(user('userId'), { index: 'userId' })
    .do(
      result => r.branch(
        result.count().eq(0),
        [{ left: user }],
        result.map(alive => ({ left: user, right: alive }))
      )
    )
  )
  .group(userAlive => ({
    appId: userAlive('left')('appId'),
    userId: userAlive('left')('userId'),
  }))
  .ungroup()
  .map(doc => ({
    appId: doc('group')('appId'),
    userId: doc('group')('userId'),
    numEvents: doc('reduction').count(),
    totalTime: doc('reduction')('right')('aliveFor').sum(),
    lastSeen: doc('reduction')('right')('receivedAt').max().default(null),
    createdAt: doc('reduction')('left')('createdAt').max().default(null),
    emails: doc('reduction')('left')('email')(0),
  }));