Ensure duplicate batch ID insertion events can't be sent

Synapse changes in matrix-org/synapse#10877

Part of MSC2716: matrix-org/matrix-spec-proposals#2716

tests/msc2716_test.go

@@ -378,6 +378,34 @@ func TestBackfillingHistory(t *testing.T) {
  )
  })
 
+ t.Run("Duplicate next_batch_id on insertion event will be rejected", func(t *testing.T) {
+ t.Parallel()
+
+ // Alice created the room and is the room creator/admin to be able to send historical events.
+ // We're using Alice over the application service so we can easily use SendEventSynced (application services can't use /sync)
+ roomID := alice.CreateRoom(t, createPublicRoomOpts)
+
+ alice.SendEventSynced(t, roomID, b.Event{
+ Type: insertionEventType,
+ Content: map[string]interface{}{
+ nextBatchIDContentField: "same",
+ historicalContentField: true,
+ },
+ })
+
+ txnId := getTxnID("duplicateinsertion-txn")
+ res := alice.DoFunc(t, "PUT", []string{"_matrix", "client", "r0", "rooms", roomID, "send", insertionEventType, txnId}, map[string]interface{}{
+ nextBatchIDContentField: "same",
+ historicalContentField: true,
+ })
+
+ // We expect the send request for the duplicate insertion event to fail
+ expectedStatus := 400
+ if res.StatusCode != expectedStatus {
+ t.Fatalf("Expected HTTP Status to be %s but received %s", expectedStatus, res.StatusCode)
+ }
+ })
+
  t.Run("Normal users aren't allowed to backfill messages", func(t *testing.T) {
  t.Parallel()