In-app test messages use the push2inapp feature, i.e. a push message with a tap action linking to an In-app message.

The push message is built in inapp service and handed over to delivery for sending the push messages. In the root params In-app campaignId 0 is used as test campaign id because the test messages should be omitted from the reporting for the campaign.

In DES campaignId 0 is considered when building oldMessages for V3 and deviceEventState for V4.

The internal events inapp:viewed and inapp:click with the campaignId 0 are still published to Pub/Sub topic api-v3-events, i.e. there are rows in BigQuery tables inapp_views and inapp_clicks with campaignId 0.