Add notificationPubsubTopic to BigQuery Data Transfer (#3881)

* Add notificationPubsubTopic to BigQuery Data Transfer

* Fix test resource names suffix to be random

products/bigquerydatatransfer/api.yaml

@@ -98,6 +98,11 @@ objects:
           about the format here:
           https://cloud.google.com/appengine/docs/flexible/python/scheduling-jobs-with-cron-yaml#the_schedule_format
           NOTE: the granularity should be at least 8 hours, or less frequent.
+      - !ruby/object:Api::Type::String
+          name: 'notificationPubsubTopic'
+          description: |
+            Pub/Sub topic where notifications will be sent after transfer runs
+            associated with this transfer config finish.
       - !ruby/object:Api::Type::Integer
         name: 'dataRefreshWindowDays'
         description: |

third_party/terraform/tests/resource_bigquery_data_transfer_config_test.go

@@ -164,6 +164,10 @@ resource "google_bigquery_dataset" "my_dataset" {
   location      = "asia-northeast1"
 }
 
+resource "google_pubsub_topic" "my_topic" {
+  name = "tf-test-my-topic-%s"
+}
+
 resource "google_bigquery_data_transfer_config" "query_config" {
   depends_on = [google_project_iam_member.permissions]
 
@@ -172,13 +176,14 @@ resource "google_bigquery_data_transfer_config" "query_config" {
   data_source_id         = "scheduled_query"
   schedule               = "%s sunday of quarter 00:00"
   destination_dataset_id = google_bigquery_dataset.my_dataset.dataset_id
+  notification_pubsub_topic = google_pubsub_topic.my_topic.id
   params = {
     destination_table_name_template = "my_table"
     write_disposition               = "WRITE_APPEND"
     query                           = "SELECT name FROM tabl WHERE x = '%s'"
   }
 }
-`, random_suffix, random_suffix, schedule, letter)
+`, random_suffix, random_suffix, random_suffix, schedule, letter)
 }
 
 func testAccBigqueryDataTransferConfig_scheduledQuery_service_account(random_suffix string) string {