Add integration test for P2P library events

[jondubois]

Description

Add an integration test to check that P2P events are triggered and with the right data.

Motivation

We don't have any integration tests which focus exclusively on events. Having this test allows us to lock down the events API and prevent regression.

Acceptance Criteria

All top level P2P library events are covered by an integration test.

[jondubois]

We now have a new philosophy for integration tests: "One test file for each feature".

To test events, we should add them as part of an existing integration feature test scenario if possible (for example, the discovery event can be tested as part of the discovery feature. The request event can be rested as part of the request feature).

If a specific event cannot be tested as part of an existing feature, we can try to come up with a new feature test which demonstrates a sample use case for that event.

The purpose of this issue is to make sure that all events are covered as part of an existing feature integration test.