Unskip dendrite skipif on a members presence test (matrix-org#516)

* Make local members presence test more reliable

and able to be ran in isolation

* add explicit presence-setting

* fix dendrite test failure

* fix imports

* apply review feedback

* add more parentheses, change skipif note, and remove additional skipif

* address review feedback

---------

Co-authored-by: kegsay <kegan@matrix.org>

tests/csapi/rooms_members_local_test.go

@@ -9,11 +9,13 @@ import (
 )
 
 func TestMembersLocal(t *testing.T) {
-	deployment := Deploy(t, b.BlueprintOneToOneRoom)
+	deployment := Deploy(t, b.BlueprintAlice)
 	defer deployment.Destroy(t)
 
 	alice := deployment.Client(t, "hs1", "@alice:hs1")
-	bob := deployment.Client(t, "hs1", "@bob:hs1")
+	// Here we don't use the BlueprintOneToOneRoom because else Bob would be able to see Alice's presence changes through
+	// that pre-existing one-on-one DM room. So we exclude that here.
+	bob := deployment.RegisterUser(t, "hs1", "bob", "bobspassword", false)
 	roomID := alice.CreateRoom(t, map[string]interface{}{"preset": "public_chat"})
 
 	bob.MustDoFunc(
@@ -23,7 +25,7 @@ func TestMembersLocal(t *testing.T) {
 		}),
 	)
 
-	_, incrementalSyncToken := alice.MustSync(t, client.SyncReq{})
+	_, incrementalSyncTokenBeforeBobJoinsRoom := alice.MustSync(t, client.SyncReq{TimeoutMillis: "0"})
 	bob.JoinRoom(t, roomID, []string{})
 
 	t.Run("Parallel", func(t *testing.T) {
@@ -38,15 +40,17 @@ func TestMembersLocal(t *testing.T) {
 		t.Run("Existing members see new members' join events", func(t *testing.T) {
 			t.Parallel()
 			// SyncJoinedTo already checks everything we need to know
-			alice.MustSyncUntil(t, client.SyncReq{}, client.SyncJoinedTo(bob.UserID, roomID))
+			alice.MustSyncUntil(t, client.SyncReq{Since: incrementalSyncTokenBeforeBobJoinsRoom}, client.SyncJoinedTo(bob.UserID, roomID))
 		})
 
 		// sytest: Existing members see new members' presence
 		// Split into initial and incremental sync cases in Complement.
-		t.Run("Existing members see new members' presence in initial sync", func(t *testing.T) {
-			runtime.SkipIf(t, runtime.Dendrite) // FIXME: https://github.com/matrix-org/dendrite/issues/2803
+		t.Run("Existing members see new members' presence (in initial sync)", func(t *testing.T) {
+			runtime.SkipIf(t, runtime.Dendrite) // FIXME: https://github.com/matrix-org/matrix-spec/issues/1374
 			t.Parallel()
+			// First we sync to make sure bob to have joined the room...
 			alice.MustSyncUntil(t, client.SyncReq{}, client.SyncJoinedTo(bob.UserID, roomID))
+			// ...and then we do another initial sync - this time waiting for bob's presence - to confirm we can get that.
 			alice.MustSyncUntil(t, client.SyncReq{},
 				client.SyncJoinedTo(bob.UserID, roomID),
 				client.SyncPresenceHas(bob.UserID, nil),
@@ -55,10 +59,9 @@ func TestMembersLocal(t *testing.T) {
 
 		// sytest: Existing members see new members' presence
 		// Split into initial and incremental sync cases in Complement.
-		t.Run("Existing members see new members' presence in incremental sync", func(t *testing.T) {
-			runtime.SkipIf(t, runtime.Dendrite) // FIXME: https://github.com/matrix-org/dendrite/issues/2803
+		t.Run("Existing members see new members' presence (in incremental sync)", func(t *testing.T) {
 			t.Parallel()
-			alice.MustSyncUntil(t, client.SyncReq{Since: incrementalSyncToken},
+			alice.MustSyncUntil(t, client.SyncReq{Since: incrementalSyncTokenBeforeBobJoinsRoom},
 				client.SyncJoinedTo(bob.UserID, roomID),
 				client.SyncPresenceHas(bob.UserID, nil),
 			)