Schema version 1.17 added serverHeartbeatStartedEvent, serverHeartbeatSucceededEvent, and serverHeartbeatFailedEvent to the observable event types in expectEvents with eventType: sdam. The runner must register a SDAM subscriber that captures heartbeat events and assert on the awaited field.

Spec: https://github.com/mongodb/specifications/blob/master/source/unified-test-format/unified-test-format.md