test(server): validate play tracker participants, scrobble buffer (#3752)

* test(server): validate play tracker participants, scrobble buffer

* tests(server): nit: remove duplicated tests and small cleanups

Signed-off-by: Deluan <deluan@navidrome.org>

* tests(server): nit: replace panics with assertions

Signed-off-by: Deluan <deluan@navidrome.org>

* just use random ids, and store it instead

---------

Signed-off-by: Deluan <deluan@navidrome.org>
Co-authored-by: Deluan <deluan@navidrome.org>

core/scrobbler/play_tracker_test.go

@@ -68,6 +68,7 @@ var _ = Describe("PlayTracker", func() {
 			Expect(fake.NowPlayingCalled).To(BeTrue())
 			Expect(fake.UserID).To(Equal("u-1"))
 			Expect(fake.Track.ID).To(Equal("123"))
+			Expect(fake.Track.Participants).To(Equal(track.Participants))
 		})
 		It("does not send track to agent if user has not authorized", func() {
 			fake.Authorized = false
@@ -132,6 +133,7 @@ var _ = Describe("PlayTracker", func() {
 			Expect(fake.ScrobbleCalled).To(BeTrue())
 			Expect(fake.UserID).To(Equal("u-1"))
 			Expect(fake.LastScrobble.ID).To(Equal("123"))
+			Expect(fake.LastScrobble.Participants).To(Equal(track.Participants))
 		})
 
 		It("increments play counts in the DB", func() {
@@ -191,7 +193,6 @@ var _ = Describe("PlayTracker", func() {
 			Expect(artist1.PlayCount).To(Equal(int64(1)))
 			Expect(artist2.PlayCount).To(Equal(int64(1)))
 		})
-
 	})
 
 })