ReactiveMongo bulk insert BSON maxSize bug

MongoBulkFailSpec.scala

package test

import org.scalatest.FunSuite
import reactivemongo.api.MongoConnection
import reactivemongo.api.collections.bson.BSONCollection
import reactivemongo.bson.{BSONDocument, BSONElement, BSONString}
import scala.concurrent.Await
import scala.concurrent.duration.Duration
import scala.util.Random
import scala.concurrent.ExecutionContext.Implicits.global

/**
 * Test for ReactiveMongo bulk insert BSON maxSize bug as discussed at:
 * @see https://groups.google.com/forum/#!topic/reactivemongo/ywcGNMnAuxA
 *
 * @author Heikki Salokanto
 * @since  2017-10-05
 */
class MongoBulkFailSpec extends FunSuite {

  private val url        = "mongodb://..."
  private val parsedUri  = MongoConnection.parseURI(url).get
  private val driver     = new reactivemongo.api.MongoDriver
  private val connection = driver.connection(parsedUri, strictUri = true).get
  private val database   = Await.result(connection.database("testdb"), Duration.Inf)

  private def makeBsonDocs(count: Int, size: Int) =
    for (i <- 1 to count) yield {
      val data = BSONString(Random.alphanumeric.take(size).mkString)
      val elem = BSONElement(i.toString, data)
      BSONDocument(Seq(elem))
    }

  test("Bulk insert succeeds") {
    val fut = database.collection[BSONCollection]("test")
      .insert(ordered = false)
      .many(makeBsonDocs(count = 10, size = 500))

    println(Await.result(fut, Duration.Inf))
  }

  test("Bulk insert fails") {
    val fut = database.collection[BSONCollection]("test")
      .insert(ordered = false)
      .many(makeBsonDocs(count = 10, size = 1500))

    println(Await.result(fut, Duration.Inf))
    
    /* throws:
    reactivemongo.core.errors.GenericDriverException: MongoError['size of document #0 exceed the maxBsonSize: 1513 > 1000']
    */
  }
}