diff --git a/config/session.go b/config/session.go
index 7ceaf56..9419038 100644
--- a/config/session.go
+++ b/config/session.go
@@ -50,6 +50,10 @@ func (config *Config) NewSession(mxid string) *Session {
 	}
 }
 
+func (s *Session) GetUserID() string {
+	return s.UserID
+}
+
 func (s *Session) Clear() {
 	s.Rooms = make(map[string]*rooms.Room)
 	s.PushRules = nil
diff --git a/matrix/rooms/member.go b/matrix/rooms/member.go
index 8fd84e9..0f7133a 100644
--- a/matrix/rooms/member.go
+++ b/matrix/rooms/member.go
@@ -45,12 +45,6 @@ type Member struct {
 
 // eventToRoomMember converts a m.room.member state event into a Member object.
 func eventToRoomMember(userID string, event *gomatrix.Event) *Member {
-	if event == nil {
-		return &Member{
-			UserID:     userID,
-			Membership: MembershipLeave,
-		}
-	}
 	membership, _ := event.Content["membership"].(string)
 	avatarURL, _ := event.Content["avatar_url"].(string)
 
diff --git a/matrix/sync.go b/matrix/sync.go
index 35a694a..f3966cb 100644
--- a/matrix/sync.go
+++ b/matrix/sync.go
@@ -25,21 +25,25 @@ import (
 	"time"
 
 	"maunium.net/go/gomatrix"
-	"maunium.net/go/gomuks/config"
 	"maunium.net/go/gomuks/matrix/rooms"
 )
 
+type SyncerSession interface {
+	GetRoom(id string) *rooms.Room
+	GetUserID() string
+}
+
 // GomuksSyncer is the default syncing implementation. You can either write your own syncer, or selectively
 // replace parts of this default syncer (e.g. the ProcessResponse method). The default syncer uses the observer
 // pattern to notify callers about incoming events. See GomuksSyncer.OnEventType for more information.
 type GomuksSyncer struct {
-	Session       *config.Session
+	Session       SyncerSession
 	listeners     map[string][]gomatrix.OnEventListener // event type to listeners array
 	FirstSyncDone bool
 }
 
 // NewGomuksSyncer returns an instantiated GomuksSyncer
-func NewGomuksSyncer(session *config.Session) *GomuksSyncer {
+func NewGomuksSyncer(session SyncerSession) *GomuksSyncer {
 	return &GomuksSyncer{
 		Session:       session,
 		listeners:     make(map[string][]gomatrix.OnEventListener),
@@ -56,7 +60,7 @@ func (s *GomuksSyncer) ProcessResponse(res *gomatrix.RespSync, since string) (er
 
 	defer func() {
 		if r := recover(); r != nil {
-			err = fmt.Errorf("ProcessResponse for %s since %s panicked: %s\n%s", s.Session.UserID, since, r, debug.Stack())
+			err = fmt.Errorf("ProcessResponse for %s since %s panicked: %s\n%s", s.Session.GetUserID(), since, r, debug.Stack())
 		}
 	}()
 
diff --git a/matrix/sync_test.go b/matrix/sync_test.go
index c5acda8..886e168 100644
--- a/matrix/sync_test.go
+++ b/matrix/sync_test.go
@@ -15,3 +15,20 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package matrix_test
+
+import (
+	"maunium.net/go/gomuks/matrix/rooms"
+)
+
+type mockSyncerSession struct {
+	rooms  map[string]*rooms.Room
+	userID string
+}
+
+func (mss *mockSyncerSession) GetRoom(id string) *rooms.Room {
+	return mss.rooms[id]
+}
+
+func (mss *mockSyncerSession) GetUserID() string {
+	return mss.userID
+}