Merge branch '1831-self-destruct-timers-private-groups' into '804-self-destructing-messages'

Update private group sharing client to include a self-destruct timer in each message

See merge request briar/briar!1303

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationManager.java

@@ -32,7 +32,7 @@ public interface GroupInvitationManager extends ConversationClient {
 	/**
 	 * The current minor version of the private group invitation client.
 	 */
-	int MINOR_VERSION = 0;
+	int MINOR_VERSION = 1;
 
 	/**
 	 * Sends an invitation to share the given private group with the given

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationRequest.java

@@ -11,8 +11,6 @@ import org.briarproject.briar.api.sharing.InvitationRequest;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
-
 @Immutable
 @NotNullByDefault
 public class GroupInvitationRequest extends InvitationRequest<PrivateGroup> {
@@ -20,9 +18,10 @@ public class GroupInvitationRequest extends InvitationRequest<PrivateGroup> {
 	public GroupInvitationRequest(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, PrivateGroup shareable,
-			@Nullable String text, boolean available, boolean canBeOpened) {
+			@Nullable String text, boolean available, boolean canBeOpened,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId, shareable,
-				text, available, canBeOpened, NO_AUTO_DELETE_TIMER);
+				text, available, canBeOpened, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationResponse.java

@@ -9,17 +9,16 @@ import org.briarproject.briar.api.sharing.InvitationResponse;
 
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
-
 @Immutable
 @NotNullByDefault
 public class GroupInvitationResponse extends InvitationResponse {
 
 	public GroupInvitationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accept, GroupId shareableId) {
+			SessionId sessionId, boolean accept, GroupId shareableId,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId,
-				accept, shareableId, NO_AUTO_DELETE_TIMER);
+				accept, shareableId, autoDeleteTimer);
 	}
 
 	@Override

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/AbstractProtocolEngine.java

@@ -23,14 +23,14 @@ import org.briarproject.briar.api.privategroup.GroupMessageFactory;
 import org.briarproject.briar.api.privategroup.PrivateGroup;
 import org.briarproject.briar.api.privategroup.PrivateGroupFactory;
 import org.briarproject.briar.api.privategroup.PrivateGroupManager;
+import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
 
 import java.util.Map;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.briar.api.privategroup.PrivateGroupManager.CLIENT_ID;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
-import static org.briarproject.briar.api.privategroup.PrivateGroupManager.MAJOR_VERSION;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.briar.privategroup.invitation.MessageType.ABORT;
 import static org.briarproject.briar.privategroup.invitation.MessageType.INVITE;
@@ -39,7 +39,7 @@ import static org.briarproject.briar.privategroup.invitation.MessageType.LEAVE;
 
 @Immutable
 @NotNullByDefault
-abstract class AbstractProtocolEngine<S extends Session>
+abstract class AbstractProtocolEngine<S extends Session<?>>
 		implements ProtocolEngine<S> {
 
 	protected final DatabaseComponent db;
@@ -90,6 +90,7 @@ abstract class AbstractProtocolEngine<S extends Session>
 		return group.getClientId().equals(PrivateGroupManager.CLIENT_ID);
 	}
 
+	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
 	boolean isValidDependency(S session, @Nullable MessageId dependency) {
 		MessageId expected = session.getLastRemoteMessageId();
 		if (dependency == null) return expected == null;
@@ -101,44 +102,83 @@ abstract class AbstractProtocolEngine<S extends Session>
 		// Apply min of preferred visibility and client's visibility
 		ContactId contactId = getContactId(txn, session.getContactGroupId());
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
-				contactId, CLIENT_ID, MAJOR_VERSION);
+				contactId, PrivateGroupManager.CLIENT_ID,
+				PrivateGroupManager.MAJOR_VERSION);
 		Visibility min = Visibility.min(preferred, client);
 		db.setGroupVisibility(txn, contactId, session.getPrivateGroupId(), min);
 	}
 
-	Message sendInviteMessage(Transaction txn, S session,
+	Message sendInviteMessage(Transaction txn, S s,
 			@Nullable String text, long timestamp, byte[] signature)
 			throws DbException {
-		Group g = db.getGroup(txn, session.getPrivateGroupId());
+		Group g = db.getGroup(txn, s.getPrivateGroupId());
 		PrivateGroup privateGroup;
 		try {
 			privateGroup = privateGroupFactory.parsePrivateGroup(g);
 		} catch (FormatException e) {
 			throw new DbException(e); // Invalid group descriptor
 		}
-		Message m = messageEncoder.encodeInviteMessage(
+		Message m;
-				session.getContactGroupId(), privateGroup.getId(),
+		if (contactSupportsAutoDeletion(txn, s.getContactGroupId())) {
-				timestamp, privateGroup.getName(), privateGroup.getCreator(),
+			// TODO: Look up the current auto-delete timer
-				privateGroup.getSalt(), text, signature);
+			long timer = NO_AUTO_DELETE_TIMER;
-		sendMessage(txn, m, INVITE, privateGroup.getId(), true);
+			m = messageEncoder.encodeInviteMessage(s.getContactGroupId(),
+					privateGroup.getId(), timestamp, privateGroup.getName(),
+					privateGroup.getCreator(), privateGroup.getSalt(), text,
+					signature, timer);
+			sendMessage(txn, m, INVITE, privateGroup.getId(), true, timer);
+		} else {
+			m = messageEncoder.encodeInviteMessage(s.getContactGroupId(),
+					privateGroup.getId(), timestamp, privateGroup.getName(),
+					privateGroup.getCreator(), privateGroup.getSalt(), text,
+					signature);
+			sendMessage(txn, m, INVITE, privateGroup.getId(), true,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
-	Message sendJoinMessage(Transaction txn, S session, boolean visibleInUi)
+	Message sendJoinMessage(Transaction txn, S s, boolean visibleInUi)
 			throws DbException {
-		Message m = messageEncoder.encodeJoinMessage(
+		Message m;
-				session.getContactGroupId(), session.getPrivateGroupId(),
+		if (contactSupportsAutoDeletion(txn, s.getContactGroupId())) {
-				getLocalTimestamp(session), session.getLastLocalMessageId());
+			// TODO: Look up the current auto-delete timer if the message is
-		sendMessage(txn, m, JOIN, session.getPrivateGroupId(), visibleInUi);
+			//   visible in the UI (accepting an invitation)
+			long timer = NO_AUTO_DELETE_TIMER;
+			m = messageEncoder.encodeJoinMessage(s.getContactGroupId(),
+					s.getPrivateGroupId(), getLocalTimestamp(s),
+					s.getLastLocalMessageId(), timer);
+			sendMessage(txn, m, JOIN, s.getPrivateGroupId(), visibleInUi,
+					timer);
+		} else {
+			m = messageEncoder.encodeJoinMessage(s.getContactGroupId(),
+					s.getPrivateGroupId(), getLocalTimestamp(s),
+					s.getLastLocalMessageId());
+			sendMessage(txn, m, JOIN, s.getPrivateGroupId(), visibleInUi,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
-	Message sendLeaveMessage(Transaction txn, S session, boolean visibleInUi)
+	Message sendLeaveMessage(Transaction txn, S s, boolean visibleInUi)
 			throws DbException {
-		Message m = messageEncoder.encodeLeaveMessage(
+		Message m;
-				session.getContactGroupId(), session.getPrivateGroupId(),
+		if (contactSupportsAutoDeletion(txn, s.getContactGroupId())) {
-				getLocalTimestamp(session), session.getLastLocalMessageId());
+			// TODO: Look up the current auto-delete timer if the message is
-		sendMessage(txn, m, LEAVE, session.getPrivateGroupId(), visibleInUi);
+			//   visible in the UI (declining an invitation)
+			long timer = NO_AUTO_DELETE_TIMER;
+			m = messageEncoder.encodeLeaveMessage(s.getContactGroupId(),
+					s.getPrivateGroupId(), getLocalTimestamp(s),
+					s.getLastLocalMessageId(), timer);
+			sendMessage(txn, m, LEAVE, s.getPrivateGroupId(), visibleInUi,
+					timer);
+		} else {
+			m = messageEncoder.encodeLeaveMessage(s.getContactGroupId(),
+					s.getPrivateGroupId(), getLocalTimestamp(s),
+					s.getLastLocalMessageId());
+			sendMessage(txn, m, LEAVE, s.getPrivateGroupId(), visibleInUi,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
@@ -146,7 +186,8 @@ abstract class AbstractProtocolEngine<S extends Session>
 		Message m = messageEncoder.encodeAbortMessage(
 				session.getContactGroupId(), session.getPrivateGroupId(),
 				getLocalTimestamp(session));
-		sendMessage(txn, m, ABORT, session.getPrivateGroupId(), false);
+		sendMessage(txn, m, ABORT, session.getPrivateGroupId(), false,
+				NO_AUTO_DELETE_TIMER);
 		return m;
 	}
 
@@ -217,11 +258,11 @@ abstract class AbstractProtocolEngine<S extends Session>
 	}
 
 	private void sendMessage(Transaction txn, Message m, MessageType type,
-			GroupId privateGroupId, boolean visibleInConversation)
+			GroupId privateGroupId, boolean visibleInConversation,
-			throws DbException {
+			long autoDeleteTimer) throws DbException {
-		BdfDictionary meta = messageEncoder
+		BdfDictionary meta = messageEncoder.encodeMetadata(type,
-				.encodeMetadata(type, privateGroupId, m.getTimestamp(), true,
+				privateGroupId, m.getTimestamp(), true, true,
-						true, visibleInConversation, false, false);
+				visibleInConversation, false, false, autoDeleteTimer);
 		try {
 			clientHelper.addLocalMessage(txn, m, meta, true, false);
 		} catch (FormatException e) {
@@ -229,4 +270,21 @@ abstract class AbstractProtocolEngine<S extends Session>
 		}
 	}
 
+	boolean contactSupportsAutoDeletion(Transaction txn, GroupId contactGroupId)
+			throws DbException {
+		try {
+			BdfDictionary meta = clientHelper
+					.getGroupMetadataAsDictionary(txn, contactGroupId);
+			int contactId = meta.getLong(GROUP_KEY_CONTACT_ID).intValue();
+			ContactId c = new ContactId(contactId);
+			int minorVersion = clientVersioningManager
+					.getClientMinorVersion(txn, c,
+							GroupInvitationManager.CLIENT_ID,
+							GroupInvitationManager.MAJOR_VERSION);
+			// Auto-delete was added in client version 0.1
+			return minorVersion >= 1;
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/CreatorProtocolEngine.java

@@ -253,10 +253,10 @@ class CreatorProtocolEngine extends AbstractProtocolEngine<CreatorSession> {
 	}
 
 	private GroupInvitationResponse createInvitationResponse(
-			GroupInvitationMessage m, boolean accept) {
+			DeletableGroupInvitationMessage m, boolean accept) {
 		SessionId sessionId = new SessionId(m.getPrivateGroupId().getBytes());
 		return new GroupInvitationResponse(m.getId(), m.getContactGroupId(),
 				m.getTimestamp(), false, false, false, false, sessionId,
-				accept, m.getPrivateGroupId());
+				accept, m.getPrivateGroupId(), m.getAutoDeleteTimer());
 	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/DeletableGroupInvitationMessage.java

@@ -0,0 +1,24 @@
+package org.briarproject.briar.privategroup.invitation;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+abstract class DeletableGroupInvitationMessage extends GroupInvitationMessage {
+
+	private final long autoDeleteTimer;
+
+	DeletableGroupInvitationMessage(MessageId id, GroupId contactGroupId,
+			GroupId privateGroupId, long timestamp, long autoDeleteTimer) {
+		super(id, contactGroupId, privateGroupId, timestamp);
+		this.autoDeleteTimer = autoDeleteTimer;
+	}
+
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
+}

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationConstants.java

@@ -13,6 +13,7 @@ interface GroupInvitationConstants {
 	String MSG_KEY_VISIBLE_IN_UI = "visibleInUi";
 	String MSG_KEY_AVAILABLE_TO_ANSWER = "availableToAnswer";
 	String MSG_KEY_INVITATION_ACCEPTED = "invitationAccepted";
+	String MSG_KEY_AUTO_DELETE_TIMER = "autoDeleteTimer";
 
 	// Session keys
 	String SESSION_KEY_IS_SESSION = "isSession";

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java

@@ -159,7 +159,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		SessionId sessionId = getSessionId(meta.getPrivateGroupId());
 		StoredSession ss = getSession(txn, m.getGroupId(), sessionId);
 		// Handle the message
-		Session session;
+		Session<?> session;
 		MessageId storageId;
 		if (ss == null) {
 			session = handleFirstMessage(txn, m, body, meta);
@@ -189,7 +189,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 				results.values().iterator().next());
 	}
 
-	private Session handleFirstMessage(Transaction txn, Message m, BdfList body,
+	private Session<?> handleFirstMessage(Transaction txn, Message m, BdfList body,
 			MessageMetadata meta) throws DbException, FormatException {
 		GroupId privateGroupId = meta.getPrivateGroupId();
 		MessageType type = meta.getMessageType();
@@ -206,7 +206,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		}
 	}
 
-	private Session handleMessage(Transaction txn, Message m, BdfList body,
+	private Session<?> handleMessage(Transaction txn, Message m, BdfList body,
 			MessageMetadata meta, BdfDictionary bdfSession)
 			throws DbException, FormatException {
 		MessageType type = meta.getMessageType();
@@ -228,7 +228,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		}
 	}
 
-	private <S extends Session> S handleMessage(Transaction txn, Message m,
+	private <S extends Session<?>> S handleMessage(Transaction txn, Message m,
 			BdfList body, MessageType type, S session, ProtocolEngine<S> engine)
 			throws DbException, FormatException {
 		if (type == INVITE) {
@@ -256,7 +256,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	}
 
 	private void storeSession(Transaction txn, MessageId storageId,
-			Session session) throws DbException, FormatException {
+			Session<?> session) throws DbException, FormatException {
 		BdfDictionary d = sessionEncoder.encodeSession(session);
 		clientHelper.mergeMessageMetadata(txn, storageId, d);
 	}
@@ -354,7 +354,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		}
 	}
 
-	private <S extends Session> S handleAction(Transaction txn,
+	private <S extends Session<?>> S handleAction(Transaction txn,
 			LocalAction type, S session, ProtocolEngine<S> engine)
 			throws DbException {
 		if (type == LocalAction.INVITE) {
@@ -420,7 +420,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		return new GroupInvitationRequest(m, contactGroupId,
 				meta.getTimestamp(), meta.isLocal(), meta.isRead(),
 				status.isSent(), status.isSeen(), sessionId, pg,
-				invite.getText(), meta.isAvailableToAnswer(), canBeOpened);
+				invite.getText(), meta.isAvailableToAnswer(), canBeOpened,
+				invite.getAutoDeleteTimer());
 	}
 
 	private GroupInvitationResponse parseInvitationResponse(
@@ -430,7 +431,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		return new GroupInvitationResponse(m, contactGroupId,
 				meta.getTimestamp(), meta.isLocal(), meta.isRead(),
 				status.isSent(), status.isSeen(), sessionId, accept,
-				meta.getPrivateGroupId());
+				meta.getPrivateGroupId(), meta.getAutoDeleteTimer());
 	}
 
 	@Override
@@ -508,7 +509,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 			SessionId sessionId = getSessionId(privateGroupId);
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
 			// Create or parse the session
-			Session session;
+			Session<?> session;
 			MessageId storageId;
 			if (ss == null) {
 				// If there's no session the contact must be a peer,
@@ -543,7 +544,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 				StoredSession ss = getSession(txn, contactGroupId, sessionId);
 				if (ss == null) continue; // No session for this contact
 				// Handle the action
-				Session session = handleAction(txn, LocalAction.LEAVE,
+				Session<?> session = handleAction(txn, LocalAction.LEAVE,
 						contactGroupId, ss.bdfSession);
 				// Store the updated session
 				storeSession(txn, ss.storageId, session);
@@ -553,7 +554,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		}
 	}
 
-	private Session handleAction(Transaction txn, LocalAction a,
+	private Session<?> handleAction(Transaction txn, LocalAction a,
 			GroupId contactGroupId, BdfDictionary bdfSession)
 			throws DbException, FormatException {
 		Role role = sessionParser.getRole(bdfSession);
@@ -613,7 +614,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 				.getMessageMetadataAsDictionary(txn, contactGroupId, query);
 		Map<GroupId, Visibility> m = new HashMap<>();
 		for (BdfDictionary d : results.values()) {
-			Session s = sessionParser.parseSession(contactGroupId, d);
+			Session<?> s = sessionParser.parseSession(contactGroupId, d);
 			m.put(s.getPrivateGroupId(), s.getState().getVisibility());
 		}
 		return m;
@@ -644,7 +645,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 			Map<GroupId, DeletableSession> sessions = new HashMap<>();
 			for (BdfDictionary d : metadata.values()) {
 				if (!sessionParser.isSession(d)) continue;
-				Session session;
+				Session<?> session;
 				try {
 					session = sessionParser.parseSession(g, d);
 				} catch (FormatException e) {
@@ -673,7 +674,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 							getSessionId(messageMetadata.getPrivateGroupId());
 					StoredSession ss = getSession(txn1, g, sessionId);
 					if (ss == null) throw new DbException();
-					Session session = sessionParser
+					Session<?> session = sessionParser
 							.parseSession(g, metadata.get(ss.storageId));
 					sessions.put(session.getPrivateGroupId(),
 							new DeletableSession(session.getState()));

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationValidator.java

@@ -21,10 +21,15 @@ import org.briarproject.briar.api.privategroup.PrivateGroupFactory;
 import java.security.GeneralSecurityException;
 import java.util.Collections;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.MAX_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.MIN_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
 import static org.briarproject.bramble.util.ValidationUtils.checkLength;
+import static org.briarproject.bramble.util.ValidationUtils.checkRange;
 import static org.briarproject.bramble.util.ValidationUtils.checkSize;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.GROUP_SALT_LENGTH;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_INVITATION_TEXT_LENGTH;
@@ -71,8 +76,11 @@ class GroupInvitationValidator extends BdfMessageValidator {
 
 	private BdfMessageContext validateInviteMessage(Message m, BdfList body)
 			throws FormatException {
-		// Message type, creator, group name, salt, optional text, signature
+		// Client version 0.0: Message type, creator, group name, salt,
-		checkSize(body, 6);
+		// optional text, signature.
+		// Client version 0.1: Message type, creator, group name, salt,
+		// optional text, signature, optional auto-delete timer.
+		checkSize(body, 6, 7);
 		BdfList creatorList = body.getList(1);
 		String groupName = body.getString(2);
 		checkLength(groupName, 1, MAX_GROUP_NAME_LENGTH);
@@ -82,6 +90,8 @@ class GroupInvitationValidator extends BdfMessageValidator {
 		checkLength(text, 1, MAX_GROUP_INVITATION_TEXT_LENGTH);
 		byte[] signature = body.getRaw(5);
 		checkLength(signature, 1, MAX_SIGNATURE_LENGTH);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 7) timer = validateTimer(body.getOptionalLong(6));
 
 		// Validate the creator and create the private group
 		Author creator = clientHelper.parseAndValidateAuthor(creatorList);
@@ -102,20 +112,27 @@ class GroupInvitationValidator extends BdfMessageValidator {
 		// Create the metadata
 		BdfDictionary meta = messageEncoder.encodeMetadata(INVITE,
 				privateGroup.getId(), m.getTimestamp(), false, false, false,
-				false, false);
+				false, false, timer);
 		return new BdfMessageContext(meta);
 	}
 
 	private BdfMessageContext validateJoinMessage(Message m, BdfList body)
 			throws FormatException {
-		checkSize(body, 3);
+		// Client version 0.0: Message type, private group ID, optional
+		// previous message ID.
+		// Client version 0.1: Message type, private group ID, optional
+		// previous message ID, optional auto-delete timer.
+		checkSize(body, 3, 4);
 		byte[] privateGroupId = body.getRaw(1);
 		checkLength(privateGroupId, UniqueId.LENGTH);
 		byte[] previousMessageId = body.getOptionalRaw(2);
 		checkLength(previousMessageId, UniqueId.LENGTH);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 4) timer = validateTimer(body.getOptionalLong(3));
+
 		BdfDictionary meta = messageEncoder.encodeMetadata(JOIN,
 				new GroupId(privateGroupId), m.getTimestamp(), false, false,
-				false, false, false);
+				false, false, false, timer);
 		if (previousMessageId == null) {
 			return new BdfMessageContext(meta);
 		} else {
@@ -127,14 +144,21 @@ class GroupInvitationValidator extends BdfMessageValidator {
 
 	private BdfMessageContext validateLeaveMessage(Message m, BdfList body)
 			throws FormatException {
-		checkSize(body, 3);
+		// Client version 0.0: Message type, private group ID, optional
+		// previous message ID.
+		// Client version 0.1: Message type, private group ID, optional
+		// previous message ID, optional auto-delete timer.
+		checkSize(body, 3, 4);
 		byte[] privateGroupId = body.getRaw(1);
 		checkLength(privateGroupId, UniqueId.LENGTH);
 		byte[] previousMessageId = body.getOptionalRaw(2);
 		checkLength(previousMessageId, UniqueId.LENGTH);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 4) timer = validateTimer(body.getOptionalLong(3));
+
 		BdfDictionary meta = messageEncoder.encodeMetadata(LEAVE,
 				new GroupId(privateGroupId), m.getTimestamp(), false, false,
-				false, false, false);
+				false, false, false, timer);
 		if (previousMessageId == null) {
 			return new BdfMessageContext(meta);
 		} else {
@@ -151,7 +175,13 @@ class GroupInvitationValidator extends BdfMessageValidator {
 		checkLength(privateGroupId, UniqueId.LENGTH);
 		BdfDictionary meta = messageEncoder.encodeMetadata(ABORT,
 				new GroupId(privateGroupId), m.getTimestamp(), false, false,
-				false, false, false);
+				false, false, false, NO_AUTO_DELETE_TIMER);
 		return new BdfMessageContext(meta);
 	}
+
+	private long validateTimer(@Nullable Long timer) throws FormatException {
+		if (timer == null) return NO_AUTO_DELETE_TIMER;
+		checkRange(timer, MIN_AUTO_DELETE_TIMER_MS, MAX_AUTO_DELETE_TIMER_MS);
+		return timer;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/InviteMessage.java

@@ -10,7 +10,7 @@ import javax.annotation.concurrent.Immutable;
 
 @Immutable
 @NotNullByDefault
-class InviteMessage extends GroupInvitationMessage {
+class InviteMessage extends DeletableGroupInvitationMessage {
 
 	private final String groupName;
 	private final Author creator;
@@ -20,8 +20,8 @@ class InviteMessage extends GroupInvitationMessage {
 
 	InviteMessage(MessageId id, GroupId contactGroupId, GroupId privateGroupId,
 			long timestamp, String groupName, Author creator, byte[] salt,
-			@Nullable String text, byte[] signature) {
+			@Nullable String text, byte[] signature, long autoDeleteTimer) {
-		super(id, contactGroupId, privateGroupId, timestamp);
+		super(id, contactGroupId, privateGroupId, timestamp, autoDeleteTimer);
 		this.groupName = groupName;
 		this.creator = creator;
 		this.salt = salt;

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/InviteeProtocolEngine.java

@@ -330,7 +330,7 @@ class InviteeProtocolEngine extends AbstractProtocolEngine<InviteeSession> {
 		SessionId sessionId = new SessionId(m.getPrivateGroupId().getBytes());
 		return new GroupInvitationRequest(m.getId(), m.getContactGroupId(),
 				m.getTimestamp(), false, false, false, false, sessionId, pg,
-				m.getText(), true, false);
+				m.getText(), true, false, m.getAutoDeleteTimer());
 	}
 
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/JoinMessage.java

@@ -9,14 +9,15 @@ import javax.annotation.concurrent.Immutable;
 
 @Immutable
 @NotNullByDefault
-class JoinMessage extends GroupInvitationMessage {
+class JoinMessage extends DeletableGroupInvitationMessage {
 
 	@Nullable
 	private final MessageId previousMessageId;
 
 	JoinMessage(MessageId id, GroupId contactGroupId, GroupId privateGroupId,
-			long timestamp, @Nullable MessageId previousMessageId) {
+			long timestamp, @Nullable MessageId previousMessageId,
-		super(id, contactGroupId, privateGroupId, timestamp);
+			long autoDeleteTimer) {
+		super(id, contactGroupId, privateGroupId, timestamp, autoDeleteTimer);
 		this.previousMessageId = previousMessageId;
 	}
 

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/LeaveMessage.java

@@ -9,14 +9,15 @@ import javax.annotation.concurrent.Immutable;
 
 @Immutable
 @NotNullByDefault
-class LeaveMessage extends GroupInvitationMessage {
+class LeaveMessage extends DeletableGroupInvitationMessage {
 
 	@Nullable
 	private final MessageId previousMessageId;
 
 	LeaveMessage(MessageId id, GroupId contactGroupId, GroupId privateGroupId,
-			long timestamp, @Nullable MessageId previousMessageId) {
+			long timestamp, @Nullable MessageId previousMessageId,
-		super(id, contactGroupId, privateGroupId, timestamp);
+			long autoDeleteTimer) {
+		super(id, contactGroupId, privateGroupId, timestamp, autoDeleteTimer);
 		this.previousMessageId = previousMessageId;
 	}
 

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/MessageEncoder.java

@@ -14,7 +14,7 @@ interface MessageEncoder {
 
 	BdfDictionary encodeMetadata(MessageType type, GroupId privateGroupId,
 			long timestamp, boolean local, boolean read, boolean visible,
-			boolean available, boolean accepted);
+			boolean available, boolean accepted, long autoDeleteTimer);
 
 	void setVisibleInUi(BdfDictionary meta, boolean visible);
 
@@ -22,16 +22,49 @@ interface MessageEncoder {
 
 	void setInvitationAccepted(BdfDictionary meta, boolean accepted);
 
+	/**
+	 * Encodes an invite message without an auto-delete timer.
+	 */
 	Message encodeInviteMessage(GroupId contactGroupId, GroupId privateGroupId,
 			long timestamp, String groupName, Author creator, byte[] salt,
 			@Nullable String text, byte[] signature);
 
+	/**
+	 * Encodes an invite message with an optional auto-delete timer. This
+	 * requires the contact to support client version 0.1 or higher.
+	 */
+	Message encodeInviteMessage(GroupId contactGroupId, GroupId privateGroupId,
+			long timestamp, String groupName, Author creator, byte[] salt,
+			@Nullable String text, byte[] signature, long autoDeleteTimer);
+
+	/**
+	 * Encodes a join message without an auto-delete timer.
+	 */
 	Message encodeJoinMessage(GroupId contactGroupId, GroupId privateGroupId,
 			long timestamp, @Nullable MessageId previousMessageId);
 
+	/**
+	 * Encodes a join message with an optional auto-delete timer. This
+	 * requires the contact to support client version 0.1 or higher.
+	 */
+	Message encodeJoinMessage(GroupId contactGroupId, GroupId privateGroupId,
+			long timestamp, @Nullable MessageId previousMessageId,
+			long autoDeleteTimer);
+
+	/**
+	 * Encodes a leave message without an auto-delete timer.
+	 */
 	Message encodeLeaveMessage(GroupId contactGroupId, GroupId privateGroupId,
 			long timestamp, @Nullable MessageId previousMessageId);
 
+	/**
+	 * Encodes a leave message with an optional auto-delete timer. This
+	 * requires the contact to support client version 0.1 or higher.
+	 */
+	Message encodeLeaveMessage(GroupId contactGroupId, GroupId privateGroupId,
+			long timestamp, @Nullable MessageId previousMessageId,
+			long autoDeleteTimer);
+
 	Message encodeAbortMessage(GroupId contactGroupId, GroupId privateGroupId,
 			long timestamp);
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/MessageEncoderImpl.java

@@ -15,7 +15,9 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.briar.client.MessageTrackerConstants.MSG_KEY_READ;
+import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_AUTO_DELETE_TIMER;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_AVAILABLE_TO_ANSWER;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_INVITATION_ACCEPTED;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_LOCAL;
@@ -45,7 +47,8 @@ class MessageEncoderImpl implements MessageEncoder {
 	@Override
 	public BdfDictionary encodeMetadata(MessageType type,
 			GroupId privateGroupId, long timestamp, boolean local, boolean read,
-			boolean visible, boolean available, boolean accepted) {
+			boolean visible, boolean available, boolean accepted,
+			long autoDeleteTimer) {
 		BdfDictionary meta = new BdfDictionary();
 		meta.put(MSG_KEY_MESSAGE_TYPE, type.getValue());
 		meta.put(MSG_KEY_PRIVATE_GROUP_ID, privateGroupId);
@@ -55,6 +58,9 @@ class MessageEncoderImpl implements MessageEncoder {
 		meta.put(MSG_KEY_VISIBLE_IN_UI, visible);
 		meta.put(MSG_KEY_AVAILABLE_TO_ANSWER, available);
 		meta.put(MSG_KEY_INVITATION_ACCEPTED, accepted);
+		if (autoDeleteTimer != NO_AUTO_DELETE_TIMER) {
+			meta.put(MSG_KEY_AUTO_DELETE_TIMER, autoDeleteTimer);
+		}
 		return meta;
 	}
 
@@ -87,12 +93,25 @@ class MessageEncoderImpl implements MessageEncoder {
 				text,
 				signature
 		);
-		try {
+		return createMessage(contactGroupId, timestamp, body);
-			return messageFactory.createMessage(contactGroupId, timestamp,
+	}
-					clientHelper.toByteArray(body));
+
-		} catch (FormatException e) {
+	@Override
-			throw new AssertionError(e);
+	public Message encodeInviteMessage(GroupId contactGroupId,
-		}
+			GroupId privateGroupId, long timestamp, String groupName,
+			Author creator, byte[] salt, @Nullable String text,
+			byte[] signature, long autoDeleteTimer) {
+		BdfList creatorList = clientHelper.toList(creator);
+		BdfList body = BdfList.of(
+				INVITE.getValue(),
+				creatorList,
+				groupName,
+				salt,
+				text,
+				signature,
+				encodeTimer(autoDeleteTimer)
+		);
+		return createMessage(contactGroupId, timestamp, body);
 	}
 
 	@Override
@@ -104,12 +123,20 @@ class MessageEncoderImpl implements MessageEncoder {
 				privateGroupId,
 				previousMessageId
 		);
-		try {
+		return createMessage(contactGroupId, timestamp, body);
-			return messageFactory.createMessage(contactGroupId, timestamp,
+	}
-					clientHelper.toByteArray(body));
+
-		} catch (FormatException e) {
+	@Override
-			throw new AssertionError(e);
+	public Message encodeJoinMessage(GroupId contactGroupId,
-		}
+			GroupId privateGroupId, long timestamp,
+			@Nullable MessageId previousMessageId, long autoDeleteTimer) {
+		BdfList body = BdfList.of(
+				JOIN.getValue(),
+				privateGroupId,
+				previousMessageId,
+				encodeTimer(autoDeleteTimer)
+		);
+		return createMessage(contactGroupId, timestamp, body);
 	}
 
 	@Override
@@ -121,12 +148,20 @@ class MessageEncoderImpl implements MessageEncoder {
 				privateGroupId,
 				previousMessageId
 		);
-		try {
+		return createMessage(contactGroupId, timestamp, body);
-			return messageFactory.createMessage(contactGroupId, timestamp,
+	}
-					clientHelper.toByteArray(body));
+
-		} catch (FormatException e) {
+	@Override
-			throw new AssertionError(e);
+	public Message encodeLeaveMessage(GroupId contactGroupId,
-		}
+			GroupId privateGroupId, long timestamp,
+			@Nullable MessageId previousMessageId, long autoDeleteTimer) {
+		BdfList body = BdfList.of(
+				LEAVE.getValue(),
+				privateGroupId,
+				previousMessageId,
+				encodeTimer(autoDeleteTimer)
+		);
+		return createMessage(contactGroupId, timestamp, body);
 	}
 
 	@Override
@@ -136,6 +171,11 @@ class MessageEncoderImpl implements MessageEncoder {
 				ABORT.getValue(),
 				privateGroupId
 		);
+		return createMessage(contactGroupId, timestamp, body);
+	}
+
+	private Message createMessage(GroupId contactGroupId, long timestamp,
+			BdfList body) {
 		try {
 			return messageFactory.createMessage(contactGroupId, timestamp,
 					clientHelper.toByteArray(body));
@@ -143,4 +183,9 @@ class MessageEncoderImpl implements MessageEncoder {
 			throw new AssertionError(e);
 		}
 	}
+
+	@Nullable
+	private Long encodeTimer(long autoDeleteTimer) {
+		return autoDeleteTimer == NO_AUTO_DELETE_TIMER ? null : autoDeleteTimer;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/MessageMetadata.java

@@ -11,12 +11,12 @@ class MessageMetadata {
 
 	private final MessageType type;
 	private final GroupId privateGroupId;
-	private final long timestamp;
+	private final long timestamp, autoDeleteTimer;
 	private final boolean local, read, visible, available, accepted;
 
 	MessageMetadata(MessageType type, GroupId privateGroupId,
 			long timestamp, boolean local, boolean read, boolean visible,
-			boolean available, boolean accepted) {
+			boolean available, boolean accepted, long autoDeleteTimer) {
 		this.privateGroupId = privateGroupId;
 		this.type = type;
 		this.timestamp = timestamp;
@@ -25,6 +25,7 @@ class MessageMetadata {
 		this.visible = visible;
 		this.available = available;
 		this.accepted = accepted;
+		this.autoDeleteTimer = autoDeleteTimer;
 	}
 
 	MessageType getMessageType() {
@@ -64,4 +65,7 @@ class MessageMetadata {
 		return accepted;
 	}
 
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/MessageParserImpl.java

@@ -8,7 +8,6 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -19,7 +18,9 @@ import org.briarproject.briar.api.privategroup.PrivateGroupFactory;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.briar.client.MessageTrackerConstants.MSG_KEY_READ;
+import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_AUTO_DELETE_TIMER;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_AVAILABLE_TO_ANSWER;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_INVITATION_ACCEPTED;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_LOCAL;
@@ -33,15 +34,12 @@ import static org.briarproject.briar.privategroup.invitation.MessageType.INVITE;
 @NotNullByDefault
 class MessageParserImpl implements MessageParser {
 
-	private final AuthorFactory authorFactory;
 	private final PrivateGroupFactory privateGroupFactory;
 	private final ClientHelper clientHelper;
 
 	@Inject
-	MessageParserImpl(AuthorFactory authorFactory,
+	MessageParserImpl(PrivateGroupFactory privateGroupFactory,
-			PrivateGroupFactory privateGroupFactory,
 			ClientHelper clientHelper) {
-		this.authorFactory = authorFactory;
 		this.privateGroupFactory = privateGroupFactory;
 		this.clientHelper = clientHelper;
 	}
@@ -82,8 +80,10 @@ class MessageParserImpl implements MessageParser {
 		boolean visible = meta.getBoolean(MSG_KEY_VISIBLE_IN_UI, false);
 		boolean available = meta.getBoolean(MSG_KEY_AVAILABLE_TO_ANSWER, false);
 		boolean accepted = meta.getBoolean(MSG_KEY_INVITATION_ACCEPTED, false);
+		long timer = meta.getLong(MSG_KEY_AUTO_DELETE_TIMER,
+				NO_AUTO_DELETE_TIMER);
 		return new MessageMetadata(type, privateGroupId, timestamp, local, read,
-				visible, available, accepted);
+				visible, available, accepted, timer);
 	}
 
 	@Override
@@ -97,39 +97,58 @@ class MessageParserImpl implements MessageParser {
 	@Override
 	public InviteMessage parseInviteMessage(Message m, BdfList body)
 			throws FormatException {
-		// Message type, creator, group name, salt, optional text, signature
+		// Client version 0.0: Message type, creator, group name, salt,
+		// optional text, signature.
+		// Client version 0.1: Message type, creator, group name, salt,
+		// optional text, signature, optional auto-delete timer.
 		BdfList creatorList = body.getList(1);
 		String groupName = body.getString(2);
 		byte[] salt = body.getRaw(3);
 		String text = body.getOptionalString(4);
 		byte[] signature = body.getRaw(5);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 7) timer = body.getLong(6, NO_AUTO_DELETE_TIMER);
 
 		Author creator = clientHelper.parseAndValidateAuthor(creatorList);
 		PrivateGroup privateGroup = privateGroupFactory.createPrivateGroup(
 				groupName, creator, salt);
 		return new InviteMessage(m.getId(), m.getGroupId(),
 				privateGroup.getId(), m.getTimestamp(), groupName, creator,
-				salt, text, signature);
+				salt, text, signature, timer);
 	}
 
 	@Override
 	public JoinMessage parseJoinMessage(Message m, BdfList body)
 			throws FormatException {
+		// Client version 0.0: Message type, private group ID, optional
+		// previous message ID.
+		// Client version 0.1: Message type, private group ID, optional
+		// previous message ID, optional auto-delete timer.
 		GroupId privateGroupId = new GroupId(body.getRaw(1));
 		byte[] b = body.getOptionalRaw(2);
 		MessageId previousMessageId = b == null ? null : new MessageId(b);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 4) timer = body.getLong(3, NO_AUTO_DELETE_TIMER);
+
 		return new JoinMessage(m.getId(), m.getGroupId(), privateGroupId,
-				m.getTimestamp(), previousMessageId);
+				m.getTimestamp(), previousMessageId, timer);
 	}
 
 	@Override
 	public LeaveMessage parseLeaveMessage(Message m, BdfList body)
 			throws FormatException {
+		// Client version 0.0: Message type, private group ID, optional
+		// previous message ID.
+		// Client version 0.1: Message type, private group ID, optional
+		// previous message ID, optional auto-delete timer.
 		GroupId privateGroupId = new GroupId(body.getRaw(1));
 		byte[] b = body.getOptionalRaw(2);
 		MessageId previousMessageId = b == null ? null : new MessageId(b);
+		long timer = NO_AUTO_DELETE_TIMER;
+		if (body.size() == 4) timer = body.getLong(3, NO_AUTO_DELETE_TIMER);
+
 		return new LeaveMessage(m.getId(), m.getGroupId(), privateGroupId,
-				m.getTimestamp(), previousMessageId);
+				m.getTimestamp(), previousMessageId, timer);
 	}
 
 	@Override

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/AbstractProtocolEngineTest.java

@@ -22,8 +22,10 @@ import org.briarproject.briar.api.privategroup.GroupMessageFactory;
 import org.briarproject.briar.api.privategroup.PrivateGroup;
 import org.briarproject.briar.api.privategroup.PrivateGroupFactory;
 import org.briarproject.briar.api.privategroup.PrivateGroupManager;
+import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
 import org.jmock.Expectations;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.test.TestUtils.getContact;
@@ -35,8 +37,6 @@ import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.GROUP_SALT_LENGTH;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_INVITATION_TEXT_LENGTH;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_NAME_LENGTH;
-import static org.briarproject.briar.api.privategroup.PrivateGroupManager.CLIENT_ID;
-import static org.briarproject.briar.api.privategroup.PrivateGroupManager.MAJOR_VERSION;
 import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.briar.privategroup.invitation.MessageType.ABORT;
 import static org.briarproject.briar.privategroup.invitation.MessageType.INVITE;
@@ -67,7 +67,8 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 	final ContactId contactId = contact.getId();
 	final Author author = contact.getAuthor();
 	final GroupId contactGroupId = new GroupId(getRandomId());
-	final Group privateGroupGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+	final Group privateGroupGroup = getGroup(PrivateGroupManager.CLIENT_ID,
+			PrivateGroupManager.MAJOR_VERSION);
 	final GroupId privateGroupId = privateGroupGroup.getId();
 	final PrivateGroup privateGroup = new PrivateGroup(privateGroupGroup,
 			getRandomString(MAX_GROUP_NAME_LENGTH), author,
@@ -80,30 +81,34 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 	final long messageTimestamp = message.getTimestamp();
 	final long inviteTimestamp = messageTimestamp - 1;
 	final long localTimestamp = inviteTimestamp - 1;
+	final BdfDictionary groupMeta = BdfDictionary.of(
+			new BdfEntry(GROUP_KEY_CONTACT_ID, contactId.getInt()));
 
 	final InviteMessage inviteMessage =
 			new InviteMessage(new MessageId(getRandomId()), contactGroupId,
 					privateGroupId, 0L, privateGroup.getName(),
 					privateGroup.getCreator(), privateGroup.getSalt(),
 					getRandomString(MAX_GROUP_INVITATION_TEXT_LENGTH),
-					signature);
+					signature, NO_AUTO_DELETE_TIMER);
 	final JoinMessage joinMessage =
 			new JoinMessage(new MessageId(getRandomId()), contactGroupId,
-					privateGroupId, 0L, lastRemoteMessageId);
+					privateGroupId, 0L, lastRemoteMessageId,
+					NO_AUTO_DELETE_TIMER);
 	final LeaveMessage leaveMessage =
 			new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-					privateGroupId, 0L, lastRemoteMessageId);
+					privateGroupId, 0L, lastRemoteMessageId,
+					NO_AUTO_DELETE_TIMER);
 	final AbortMessage abortMessage =
 			new AbortMessage(messageId, contactGroupId, privateGroupId,
 					inviteTimestamp + 1);
 
-	void assertSessionConstantsUnchanged(Session s1, Session s2) {
+	void assertSessionConstantsUnchanged(Session<?> s1, Session<?> s2) {
 		assertEquals(s1.getRole(), s2.getRole());
 		assertEquals(s1.getContactGroupId(), s2.getContactGroupId());
 		assertEquals(s1.getPrivateGroupId(), s2.getPrivateGroupId());
 	}
 
-	void assertSessionRecordedSentMessage(Session s) {
+	void assertSessionRecordedSentMessage(Session<?> s) {
 		assertEquals(messageId, s.getLastLocalMessageId());
 		assertEquals(lastRemoteMessageId, s.getLastRemoteMessageId());
 		assertEquals(messageTimestamp, s.getLocalTimestamp());
@@ -118,11 +123,13 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 	}
 
 	void expectSendInviteMessage(String text) throws Exception {
+		expectCheckWhetherContactSupportsAutoDeletion();
+		expectGetLocalTimestamp(messageTimestamp);
 		context.checking(new Expectations() {{
-			oneOf(messageEncoder)
+			oneOf(messageEncoder).encodeInviteMessage(contactGroupId,
-					.encodeInviteMessage(contactGroupId, privateGroupId,
+					privateGroupId, inviteTimestamp, privateGroup.getName(),
-							inviteTimestamp, privateGroup.getName(), author,
+					author, privateGroup.getSalt(), text, signature,
-							privateGroup.getSalt(), text, signature);
+					NO_AUTO_DELETE_TIMER);
 			will(returnValue(message));
 		}});
 		expectSendMessage(INVITE, true);
@@ -130,22 +137,24 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 
 	void expectSendJoinMessage(JoinMessage m, boolean visible)
 			throws Exception {
+		expectCheckWhetherContactSupportsAutoDeletion();
 		expectGetLocalTimestamp(messageTimestamp);
 		context.checking(new Expectations() {{
 			oneOf(messageEncoder).encodeJoinMessage(m.getContactGroupId(),
 					m.getPrivateGroupId(), m.getTimestamp(),
-					lastLocalMessageId);
+					lastLocalMessageId, NO_AUTO_DELETE_TIMER);
 			will(returnValue(message));
 		}});
 		expectSendMessage(JOIN, visible);
 	}
 
 	void expectSendLeaveMessage(boolean visible) throws Exception {
+		expectCheckWhetherContactSupportsAutoDeletion();
 		expectGetLocalTimestamp(messageTimestamp);
 		context.checking(new Expectations() {{
-			oneOf(messageEncoder)
+			oneOf(messageEncoder).encodeLeaveMessage(contactGroupId,
-					.encodeLeaveMessage(contactGroupId, privateGroupId,
+					privateGroupId, messageTimestamp, lastLocalMessageId,
-							messageTimestamp, lastLocalMessageId);
+					NO_AUTO_DELETE_TIMER);
 			will(returnValue(message));
 		}});
 		expectSendMessage(LEAVE, visible);
@@ -167,7 +176,8 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 		BdfDictionary meta = BdfDictionary.of(new BdfEntry("me", "ta"));
 		context.checking(new Expectations() {{
 			oneOf(messageEncoder).encodeMetadata(type, privateGroupId,
-					message.getTimestamp(), true, true, visible, false, false);
+					message.getTimestamp(), true, true, visible, false, false,
+					NO_AUTO_DELETE_TIMER);
 			will(returnValue(meta));
 			oneOf(clientHelper).addLocalMessage(txn, message, meta, true,
 					false);
@@ -178,7 +188,8 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 		expectGetContactId();
 		context.checking(new Expectations() {{
 			oneOf(clientVersioningManager).getClientVisibility(txn, contactId,
-					CLIENT_ID, MAJOR_VERSION);
+					PrivateGroupManager.CLIENT_ID,
+					PrivateGroupManager.MAJOR_VERSION);
 			will(returnValue(SHARED));
 			oneOf(db).setGroupVisibility(txn, contactId, privateGroupId, v);
 		}});
@@ -218,4 +229,15 @@ abstract class AbstractProtocolEngineTest extends BrambleMockTestCase {
 		}});
 	}
 
+	void expectCheckWhetherContactSupportsAutoDeletion() throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(groupMeta));
+			oneOf(clientVersioningManager).getClientMinorVersion(txn, contactId,
+					GroupInvitationManager.CLIENT_ID,
+					GroupInvitationManager.MAJOR_VERSION);
+			will(returnValue(GroupInvitationManager.MINOR_VERSION));
+		}});
+	}
 }

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/CreatorProtocolEngineTest.java

@@ -5,6 +5,7 @@ import org.briarproject.briar.api.client.ProtocolStateException;
 import org.jmock.Expectations;
 import org.junit.Test;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
@@ -77,7 +78,6 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 			oneOf(messageTracker).trackOutgoingMessage(txn, message);
 		}});
 		expectSendInviteMessage(text);
-		expectGetLocalTimestamp(messageTimestamp);
 	}
 
 	@Test(expected = ProtocolStateException.class)
@@ -289,7 +289,7 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 		CreatorSession session = getDefaultSession(INVITED);
 		JoinMessage invalidJoinMessage =
 				new JoinMessage(messageId, contactGroupId, privateGroupId,
-						inviteTimestamp + 1, messageId);
+						inviteTimestamp + 1, messageId, NO_AUTO_DELETE_TIMER);
 
 		expectAbortWhenSubscribedToGroup();
 		CreatorSession newSession =
@@ -303,7 +303,7 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 		JoinMessage properJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, inviteTimestamp + 1,
-						lastRemoteMessageId);
+						lastRemoteMessageId, NO_AUTO_DELETE_TIMER);
 
 		expectSendJoinMessage(properJoinMessage, false);
 		expectMarkMessageVisibleInUi(properJoinMessage.getId());
@@ -343,7 +343,8 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 	public void testOnLeaveMessageFromStart() throws Exception {
 		LeaveMessage leaveMessage =
 				new LeaveMessage(messageId, contactGroupId, privateGroupId,
-						inviteTimestamp, lastLocalMessageId);
+						inviteTimestamp, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		CreatorSession session = getDefaultSession(START);
 
 		expectAbortWhenSubscribedToGroup();
@@ -377,7 +378,8 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(messageId, contactGroupId, privateGroupId,
-						inviteTimestamp + 1, lastLocalMessageId);
+						inviteTimestamp + 1, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		CreatorSession session = getDefaultSession(INVITED);
 
 		expectAbortWhenSubscribedToGroup();
@@ -392,7 +394,7 @@ public class CreatorProtocolEngineTest extends AbstractProtocolEngineTest {
 		LeaveMessage properLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, inviteTimestamp + 1,
-						lastRemoteMessageId);
+						lastRemoteMessageId, NO_AUTO_DELETE_TIMER);
 		CreatorSession session = getDefaultSession(INVITED);
 
 		expectMarkMessageVisibleInUi(properLeaveMessage.getId());

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImplTest.java

@@ -45,6 +45,7 @@ import javax.annotation.Nullable;
 
 import static java.util.Arrays.asList;
 import static junit.framework.TestCase.fail;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getContact;
@@ -230,7 +231,7 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		}});
 	}
 
-	private void expectStoreSession(Session session, MessageId storageId)
+	private void expectStoreSession(Session<?> session, MessageId storageId)
 			throws Exception {
 		context.checking(new Expectations() {{
 			oneOf(sessionEncoder).encodeSession(session);
@@ -320,7 +321,8 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			throws Exception {
 		expectParseMessageMetadata();
 		expectGetSession(noResults, sessionId, contactGroup.getId());
-		Session session = expectHandleFirstMessage(role, messageMetadata, type);
+		Session<?> session =
+				expectHandleFirstMessage(role, messageMetadata, type);
 		if (session != null) {
 			expectCreateStorageId();
 			expectStoreSession(session, storageMessage.getId());
@@ -347,13 +349,13 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			BdfDictionary bdfSession) throws Exception {
 		expectParseMessageMetadata();
 		expectGetSession(oneResult, sessionId, contactGroup.getId());
-		Session session = expectHandleMessage(role, messageMetadata, bdfSession,
+		Session<?> session =
-				type);
+				expectHandleMessage(role, messageMetadata, bdfSession, type);
 		expectStoreSession(session, storageMessage.getId());
 	}
 
 	@Nullable
-	private Session expectHandleFirstMessage(Role role,
+	private Session<?> expectHandleFirstMessage(Role role,
 			MessageMetadata messageMetadata, MessageType type)
 			throws Exception {
 		context.checking(new Expectations() {{
@@ -382,7 +384,7 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Nullable
-	private Session expectHandleMessage(Role role,
+	private Session<?> expectHandleMessage(Role role,
 			MessageMetadata messageMetadata, BdfDictionary state,
 			MessageType type) throws Exception {
 		context.checking(new Expectations() {{
@@ -420,8 +422,9 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		}
 	}
 
-	private <S extends Session> void expectIndividualMessage(MessageType type,
+	private <S extends Session<?>> void expectIndividualMessage(
-			ProtocolEngine<S> engine, S session) throws Exception {
+			MessageType type, ProtocolEngine<S> engine, S session)
+			throws Exception {
 		if (type == INVITE) {
 			InviteMessage msg = context.mock(InviteMessage.class);
 			context.checking(new Expectations() {{
@@ -657,14 +660,14 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		long time1 = 1L, time2 = 2L;
 		MessageMetadata messageMetadata1 =
 				new MessageMetadata(INVITE, privateGroup.getId(), time1, true,
-						true, true, false, true);
+						true, true, false, true, NO_AUTO_DELETE_TIMER);
 		MessageMetadata messageMetadata2 =
 				new MessageMetadata(JOIN, privateGroup.getId(), time2, true,
-						true, true, true, false);
+						true, true, true, false, NO_AUTO_DELETE_TIMER);
 		InviteMessage invite =
 				new InviteMessage(message.getId(), contactGroup.getId(),
 						privateGroup.getId(), time1, "name", author,
-						new byte[0], null, new byte[0]);
+						new byte[0], null, new byte[0], NO_AUTO_DELETE_TIMER);
 		PrivateGroup pg =
 				new PrivateGroup(privateGroup, invite.getGroupName(),
 						invite.getCreator(), invite.getSalt());
@@ -731,11 +734,11 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		InviteMessage inviteMessage1 =
 				new InviteMessage(message.getId(), contactGroup.getId(),
 						privateGroup.getId(), time1, groupName, author, salt,
-						null, getRandomBytes(5));
+						null, getRandomBytes(5), NO_AUTO_DELETE_TIMER);
 		InviteMessage inviteMessage2 =
 				new InviteMessage(message2.getId(), contactGroup.getId(),
 						privateGroup.getId(), time2, groupName, author, salt,
-						null, getRandomBytes(5));
+						null, getRandomBytes(5), NO_AUTO_DELETE_TIMER);
 		PrivateGroup pg = new PrivateGroup(privateGroup, groupName,
 				author, salt);
 

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/GroupInvitationValidatorTest.java

@@ -16,6 +16,11 @@ import org.junit.Test;
 
 import java.security.GeneralSecurityException;
 
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.MAX_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.MIN_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
@@ -25,12 +30,12 @@ import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.GROU
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_INVITATION_TEXT_LENGTH;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_NAME_LENGTH;
 import static org.briarproject.briar.api.privategroup.invitation.GroupInvitationFactory.SIGNING_LABEL_INVITE;
+import static org.briarproject.briar.privategroup.invitation.GroupInvitationConstants.MSG_KEY_AUTO_DELETE_TIMER;
 import static org.briarproject.briar.privategroup.invitation.MessageType.ABORT;
 import static org.briarproject.briar.privategroup.invitation.MessageType.INVITE;
 import static org.briarproject.briar.privategroup.invitation.MessageType.JOIN;
 import static org.briarproject.briar.privategroup.invitation.MessageType.LEAVE;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
 
 public class GroupInvitationValidatorTest extends ValidatorTestCase {
 
@@ -71,7 +76,7 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	@Test(expected = FormatException.class)
 	public void testRejectsTooLongInviteMessage() throws Exception {
 		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
-				salt, text, signature, "");
+				salt, text, signature, NO_AUTO_DELETE_TIMER, null);
 		validator.validateMessage(message, group, body);
 	}
 
@@ -182,8 +187,7 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	public void testAcceptsInviteMessageWithNullText() throws Exception {
 		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
 				salt, null, signature);
-		expectInviteMessage(false);
+		testAcceptsInviteMessage(body, NO_AUTO_DELETE_TIMER, meta);
-		validator.validateMessage(message, group, body);
 	}
 
 	@Test(expected = FormatException.class)
@@ -233,15 +237,73 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 		validator.validateMessage(message, group, body);
 	}
 
+	@Test(expected = FormatException.class)
+	public void testRejectsInviteMessageWithTooBigAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, MAX_AUTO_DELETE_TIMER_MS + 1);
+		validator.validateMessage(message, group, body);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsInviteMessageWithTooSmallAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, MIN_AUTO_DELETE_TIMER_MS - 1);
+		validator.validateMessage(message, group, body);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsInviteMessageWithNonLongAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, "foo");
+		validator.validateMessage(message, group, body);
+	}
+
 	@Test
 	public void testAcceptsValidInviteMessage() throws Exception {
 		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
 				salt, text, signature);
+		testAcceptsInviteMessage(body, NO_AUTO_DELETE_TIMER, meta);
+	}
+
+	@Test
+	public void testAcceptsInviteMessageWithNullAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, null);
+		testAcceptsInviteMessage(body, NO_AUTO_DELETE_TIMER, meta);
+	}
+
+	@Test
+	public void testAcceptsInviteMessageWithMinAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, MIN_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MIN_AUTO_DELETE_TIMER_MS);
+		testAcceptsInviteMessage(body, MIN_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	@Test
+	public void testAcceptsInviteMessageWithMaxAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(INVITE.getValue(), creatorList, groupName,
+				salt, text, signature, MAX_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MAX_AUTO_DELETE_TIMER_MS);
+		testAcceptsInviteMessage(body, MAX_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	private void testAcceptsInviteMessage(BdfList body, long autoDeleteTimer,
+			BdfDictionary metadata) throws Exception {
 		expectInviteMessage(false);
+		expectEncodeMetadata(INVITE, autoDeleteTimer, metadata);
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertTrue(messageContext.getDependencies().isEmpty());
+		assertEquals(emptyList(), messageContext.getDependencies());
-		assertEquals(meta, messageContext.getDictionary());
+		assertEquals(metadata, messageContext.getDictionary());
 	}
 
 	private void expectInviteMessage(boolean exception) throws Exception {
@@ -260,11 +322,6 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 					signed, creator.getPublicKey());
 			if (exception) {
 				will(throwException(new GeneralSecurityException()));
-			} else {
-				oneOf(messageEncoder).encodeMetadata(INVITE,
-						message.getGroupId(), message.getTimestamp(), false,
-						false, false, false, false);
-				will(returnValue(meta));
 			}
 		}});
 	}
@@ -280,7 +337,7 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	@Test(expected = FormatException.class)
 	public void testRejectsTooLongJoinMessage() throws Exception {
 		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(),
-				previousMessageId, "");
+				previousMessageId, NO_AUTO_DELETE_TIMER, null);
 		validator.validateMessage(message, group, body);
 	}
 
@@ -339,14 +396,10 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	public void testAcceptsJoinMessageWithNullPreviousMessageId()
 			throws Exception {
 		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(), null);
-		context.checking(new Expectations() {{
+		expectEncodeMetadata(JOIN, NO_AUTO_DELETE_TIMER, meta);
-			oneOf(messageEncoder).encodeMetadata(JOIN, message.getGroupId(),
-					message.getTimestamp(), false, false, false, false, false);
-			will(returnValue(meta));
-		}});
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertEquals(0, messageContext.getDependencies().size());
+		assertEquals(emptyList(), messageContext.getDependencies());
 		assertEquals(meta, messageContext.getDictionary());
 	}
 
@@ -354,17 +407,45 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	public void testAcceptsValidJoinMessage() throws Exception {
 		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(),
 				previousMessageId);
-		context.checking(new Expectations() {{
+		testAcceptsJoinMessage(body, NO_AUTO_DELETE_TIMER, meta);
-			oneOf(messageEncoder).encodeMetadata(JOIN, message.getGroupId(),
+	}
-					message.getTimestamp(), false, false, false, false, false);
+
-			will(returnValue(meta));
+	@Test
-		}});
+	public void testAcceptsJoinMessageWithNullAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(),
+				previousMessageId, null);
+		testAcceptsJoinMessage(body, NO_AUTO_DELETE_TIMER, meta);
+	}
+
+	@Test
+	public void testAcceptsJoinMessageWitMinAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(),
+				previousMessageId, MIN_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MIN_AUTO_DELETE_TIMER_MS);
+		testAcceptsJoinMessage(body, MIN_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	@Test
+	public void testAcceptsJoinMessageWitMaxAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(JOIN.getValue(), privateGroup.getId(),
+				previousMessageId, MAX_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MAX_AUTO_DELETE_TIMER_MS);
+		testAcceptsJoinMessage(body, MAX_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	private void testAcceptsJoinMessage(BdfList body, long autoDeleteTimer,
+			BdfDictionary metadata) throws Exception {
+		expectEncodeMetadata(JOIN, autoDeleteTimer, metadata);
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertEquals(1, messageContext.getDependencies().size());
+		assertEquals(singletonList(previousMessageId),
-		assertEquals(previousMessageId,
+				messageContext.getDependencies());
-				messageContext.getDependencies().iterator().next());
+		assertEquals(metadata, messageContext.getDictionary());
-		assertEquals(meta, messageContext.getDictionary());
 	}
 
 	// LEAVE message
@@ -437,32 +518,56 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 	public void testAcceptsLeaveMessageWithNullPreviousMessageId()
 			throws Exception {
 		BdfList body = BdfList.of(LEAVE.getValue(), privateGroup.getId(), null);
-		context.checking(new Expectations() {{
+		expectEncodeMetadata(LEAVE, NO_AUTO_DELETE_TIMER, meta);
-			oneOf(messageEncoder).encodeMetadata(LEAVE, message.getGroupId(),
-					message.getTimestamp(), false, false, false, false, false);
-			will(returnValue(meta));
-		}});
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertEquals(0, messageContext.getDependencies().size());
+		assertEquals(emptyList(), messageContext.getDependencies());
 		assertEquals(meta, messageContext.getDictionary());
 	}
 
 	@Test
 	public void testAcceptsValidLeaveMessage() throws Exception {
-		context.checking(new Expectations() {{
-			oneOf(messageEncoder).encodeMetadata(LEAVE, message.getGroupId(),
-					message.getTimestamp(), false, false, false, false, false);
-			will(returnValue(meta));
-		}});
 		BdfList body = BdfList.of(LEAVE.getValue(), privateGroup.getId(),
 				previousMessageId);
+		testAcceptsLeaveMessage(body, NO_AUTO_DELETE_TIMER, meta);
+	}
+
+	@Test
+	public void testAcceptsLeaveMessageWithNullAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(LEAVE.getValue(), privateGroup.getId(),
+				previousMessageId, null);
+		testAcceptsLeaveMessage(body, NO_AUTO_DELETE_TIMER, meta);
+	}
+
+	@Test
+	public void testAcceptsLeaveMessageWithMinAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(LEAVE.getValue(), privateGroup.getId(),
+				previousMessageId, MIN_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MIN_AUTO_DELETE_TIMER_MS);
+		testAcceptsLeaveMessage(body, MIN_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	@Test
+	public void testAcceptsLeaveMessageWithMaxAutoDeleteTimer()
+			throws Exception {
+		BdfList body = BdfList.of(LEAVE.getValue(), privateGroup.getId(),
+				previousMessageId, MAX_AUTO_DELETE_TIMER_MS);
+		BdfDictionary metadata = new BdfDictionary(meta);
+		metadata.put(MSG_KEY_AUTO_DELETE_TIMER, MAX_AUTO_DELETE_TIMER_MS);
+		testAcceptsLeaveMessage(body, MAX_AUTO_DELETE_TIMER_MS, metadata);
+	}
+
+	private void testAcceptsLeaveMessage(BdfList body, long autoDeleteTimer,
+			BdfDictionary metadata) throws Exception {
+		expectEncodeMetadata(LEAVE, autoDeleteTimer, metadata);
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertEquals(1, messageContext.getDependencies().size());
+		assertEquals(singletonList(previousMessageId),
-		assertEquals(previousMessageId,
+				messageContext.getDependencies());
-				messageContext.getDependencies().iterator().next());
+		assertEquals(metadata, messageContext.getDictionary());
-		assertEquals(meta, messageContext.getDictionary());
 	}
 
 	// ABORT message
@@ -507,15 +612,11 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 
 	@Test
 	public void testAcceptsValidAbortMessage() throws Exception {
-		context.checking(new Expectations() {{
-			oneOf(messageEncoder).encodeMetadata(ABORT, message.getGroupId(),
-					message.getTimestamp(), false, false, false, false, false);
-			will(returnValue(meta));
-		}});
 		BdfList body = BdfList.of(ABORT.getValue(), privateGroup.getId());
+		expectEncodeMetadata(ABORT, NO_AUTO_DELETE_TIMER, meta);
 		BdfMessageContext messageContext =
 				validator.validateMessage(message, group, body);
-		assertEquals(0, messageContext.getDependencies().size());
+		assertEquals(emptyList(), messageContext.getDependencies());
 		assertEquals(meta, messageContext.getDictionary());
 	}
 
@@ -531,4 +632,13 @@ public class GroupInvitationValidatorTest extends ValidatorTestCase {
 		validator.validateMessage(message, group, body);
 	}
 
+	private void expectEncodeMetadata(MessageType type,
+			long autoDeleteTimer, BdfDictionary metadata) {
+		context.checking(new Expectations() {{
+			oneOf(messageEncoder).encodeMetadata(type, message.getGroupId(),
+					message.getTimestamp(), false, false, false, false, false,
+					autoDeleteTimer);
+			will(returnValue(metadata));
+		}});
+	}
 }

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/InviteeProtocolEngineTest.java

@@ -13,6 +13,7 @@ import org.junit.Test;
 import java.util.Collections;
 import java.util.Map;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
@@ -131,7 +132,8 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 	public void testOnJoinActionFromInvited() throws Exception {
 		JoinMessage properJoinMessage =
 				new JoinMessage(messageId, contactGroupId, privateGroupId,
-						messageTimestamp, lastRemoteMessageId);
+						messageTimestamp, lastRemoteMessageId,
+						NO_AUTO_DELETE_TIMER);
 		long timestamp = 0L;
 		GroupMessage joinGroupMessage =
 				new GroupMessage(message, null, localAuthor);
@@ -329,7 +331,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 						privateGroup.getName(), privateGroup.getCreator(),
 						privateGroup.getSalt(),
 						getRandomString(MAX_GROUP_INVITATION_TEXT_LENGTH),
-						signature);
+						signature, NO_AUTO_DELETE_TIMER);
 		Contact notCreatorContact = getContact(contactId, getAuthor(),
 				localAuthor.getId(), true);
 
@@ -352,7 +354,8 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 				new InviteMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, session.getInviteTimestamp() + 1,
 						privateGroup.getName(), privateGroup.getCreator(),
-						privateGroup.getSalt(), "msg", signature);
+						privateGroup.getSalt(), "msg", signature,
+						NO_AUTO_DELETE_TIMER);
 		assertEquals(contact.getAuthor(), privateGroup.getCreator());
 
 		expectGetContactId();
@@ -505,7 +508,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		JoinMessage invalidJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, session.getInviteTimestamp() + 1,
-						lastLocalMessageId);
+						lastLocalMessageId, NO_AUTO_DELETE_TIMER);
 		assertFalse(invalidJoinMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNotNull(session.getLastRemoteMessageId());
@@ -525,7 +528,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		JoinMessage properJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, session.getInviteTimestamp() + 1,
-						lastRemoteMessageId);
+						lastRemoteMessageId, NO_AUTO_DELETE_TIMER);
 		assertFalse(properJoinMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNotNull(session.getLastRemoteMessageId());
@@ -607,7 +610,8 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		InviteeSession session = getDefaultSession(INVITED);
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, session.getInviteTimestamp() + 1, null);
+						privateGroupId, session.getInviteTimestamp() + 1, null,
+						NO_AUTO_DELETE_TIMER);
 		assertFalse(invalidLeaveMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNull(invalidLeaveMessage.getPreviousMessageId());
@@ -624,7 +628,8 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		InviteeSession session = getDefaultSession(LEFT);
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, session.getInviteTimestamp() + 1, null);
+						privateGroupId, session.getInviteTimestamp() + 1, null,
+						NO_AUTO_DELETE_TIMER);
 		assertFalse(invalidLeaveMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNull(invalidLeaveMessage.getPreviousMessageId());
@@ -641,7 +646,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		LeaveMessage properLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, session.getInviteTimestamp() + 1,
-						lastRemoteMessageId);
+						lastRemoteMessageId, NO_AUTO_DELETE_TIMER);
 		assertFalse(properLeaveMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNotNull(session.getLastRemoteMessageId());
@@ -671,7 +676,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 		LeaveMessage properLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
 						privateGroupId, session.getInviteTimestamp() + 1,
-						lastRemoteMessageId);
+						lastRemoteMessageId, NO_AUTO_DELETE_TIMER);
 		assertFalse(properLeaveMessage.getTimestamp() <=
 				session.getInviteTimestamp());
 		assertNotNull(session.getLastRemoteMessageId());

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/PeerProtocolEngineTest.java

@@ -5,6 +5,7 @@ import org.briarproject.briar.api.client.ProtocolStateException;
 import org.jmock.Expectations;
 import org.junit.Test;
 
+import static org.briarproject.bramble.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
@@ -17,9 +18,8 @@ import static org.briarproject.briar.privategroup.invitation.PeerState.LOCAL_LEF
 import static org.briarproject.briar.privategroup.invitation.PeerState.NEITHER_JOINED;
 import static org.briarproject.briar.privategroup.invitation.PeerState.START;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
 
 public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 
@@ -37,43 +37,43 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 	// onInviteAction
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromStart() throws Exception {
+	public void testOnInviteActionFromStart() {
 		engine.onInviteAction(txn, getDefaultSession(START), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromAwaitMember() throws Exception {
+	public void testOnInviteActionFromAwaitMember() {
 		engine.onInviteAction(txn, getDefaultSession(AWAIT_MEMBER), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromNeitherJoined() throws Exception {
+	public void testOnInviteActionFromNeitherJoined() {
 		engine.onInviteAction(txn, getDefaultSession(NEITHER_JOINED), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromLocalJoined() throws Exception {
+	public void testOnInviteActionFromLocalJoined() {
 		engine.onInviteAction(txn, getDefaultSession(LOCAL_JOINED), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromBothJoined() throws Exception {
+	public void testOnInviteActionFromBothJoined() {
 		engine.onInviteAction(txn, getDefaultSession(BOTH_JOINED), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromLocalLeft() throws Exception {
+	public void testOnInviteActionFromLocalLeft() {
 		engine.onInviteAction(txn, getDefaultSession(LOCAL_LEFT), null,
 				messageTimestamp, signature);
 	}
 
 	@Test(expected = UnsupportedOperationException.class)
-	public void testOnInviteActionFromError() throws Exception {
+	public void testOnInviteActionFromError() {
 		engine.onInviteAction(txn, getDefaultSession(ERROR), null,
 				messageTimestamp, signature);
 	}
@@ -109,7 +109,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 	public void testOnJoinActionFromNeitherJoined() throws Exception {
 		JoinMessage joinMessage =
 				new JoinMessage(messageId, contactGroupId,
-						privateGroupId, messageTimestamp, lastRemoteMessageId);
+						privateGroupId, messageTimestamp, lastRemoteMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(NEITHER_JOINED);
 
 		expectSendJoinMessage(joinMessage, false);
@@ -125,7 +126,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 	public void testOnJoinActionFromLocalLeft() throws Exception {
 		JoinMessage joinMessage =
 				new JoinMessage(messageId, contactGroupId,
-						privateGroupId, messageTimestamp, lastRemoteMessageId);
+						privateGroupId, messageTimestamp, lastRemoteMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(LOCAL_LEFT);
 
 		expectSendJoinMessage(joinMessage, false);
@@ -216,7 +218,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 	public void testOnMemberAddedFromAwaitMember() throws Exception {
 		JoinMessage joinMessage =
 				new JoinMessage(messageId, contactGroupId,
-						privateGroupId, messageTimestamp, lastRemoteMessageId);
+						privateGroupId, messageTimestamp, lastRemoteMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(AWAIT_MEMBER);
 
 		expectSendJoinMessage(joinMessage, false);
@@ -361,12 +364,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		JoinMessage invalidJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(START);
 		assertNotNull(invalidJoinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidJoinMessage.getPreviousMessageId()
+		assertNotEquals(invalidJoinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenNotSubscribedToGroup();
 		PeerSession newSession =
@@ -379,8 +383,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(START);
 		assertNotNull(joinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(joinMessage.getPreviousMessageId()
+		assertEquals(joinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		PeerSession newSession =
 				engine.onJoinMessage(txn, session, joinMessage);
@@ -399,12 +403,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		JoinMessage invalidJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(NEITHER_JOINED);
 		assertNotNull(invalidJoinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidJoinMessage.getPreviousMessageId()
+		assertNotEquals(invalidJoinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenNotSubscribedToGroup();
 		PeerSession newSession =
@@ -417,10 +422,11 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(NEITHER_JOINED);
 		assertNotNull(joinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(joinMessage.getPreviousMessageId()
+		assertEquals(joinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 		JoinMessage myJoinMessage = new JoinMessage(messageId, contactGroupId,
-				privateGroupId, messageTimestamp, lastRemoteMessageId);
+				privateGroupId, messageTimestamp, lastRemoteMessageId,
+				NO_AUTO_DELETE_TIMER);
 
 		expectSendJoinMessage(myJoinMessage, false);
 		expectSetPrivateGroupVisibility(SHARED);
@@ -441,12 +447,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		JoinMessage invalidJoinMessage =
 				new JoinMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(LOCAL_JOINED);
 		assertNotNull(invalidJoinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidJoinMessage.getPreviousMessageId()
+		assertNotEquals(invalidJoinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenNotSubscribedToGroup();
 		PeerSession newSession =
@@ -459,8 +466,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(LOCAL_JOINED);
 		assertNotNull(joinMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(joinMessage.getPreviousMessageId()
+		assertEquals(joinMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectSetPrivateGroupVisibility(SHARED);
 		expectRelationshipRevealed(false);
@@ -520,12 +527,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(AWAIT_MEMBER);
 		assertNotNull(invalidLeaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidLeaveMessage.getPreviousMessageId()
+		assertNotEquals(invalidLeaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenSubscribedToGroup();
 		PeerSession newSession =
@@ -538,8 +546,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(AWAIT_MEMBER);
 		assertNotNull(leaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(leaveMessage.getPreviousMessageId()
+		assertEquals(leaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		PeerSession newSession =
 				engine.onLeaveMessage(txn, session, leaveMessage);
@@ -558,12 +566,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(LOCAL_LEFT);
 		assertNotNull(invalidLeaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidLeaveMessage.getPreviousMessageId()
+		assertNotEquals(invalidLeaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenSubscribedToGroup();
 		PeerSession newSession =
@@ -576,8 +585,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(LOCAL_LEFT);
 		assertNotNull(leaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(leaveMessage.getPreviousMessageId()
+		assertEquals(leaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		PeerSession newSession =
 				engine.onLeaveMessage(txn, session, leaveMessage);
@@ -596,12 +605,13 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 			throws Exception {
 		LeaveMessage invalidLeaveMessage =
 				new LeaveMessage(new MessageId(getRandomId()), contactGroupId,
-						privateGroupId, 0L, lastLocalMessageId);
+						privateGroupId, 0L, lastLocalMessageId,
+						NO_AUTO_DELETE_TIMER);
 		PeerSession session = getDefaultSession(BOTH_JOINED);
 		assertNotNull(invalidLeaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertFalse(invalidLeaveMessage.getPreviousMessageId()
+		assertNotEquals(invalidLeaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectAbortWhenSubscribedToGroup();
 		PeerSession newSession =
@@ -614,8 +624,8 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 		PeerSession session = getDefaultSession(BOTH_JOINED);
 		assertNotNull(leaveMessage.getPreviousMessageId());
 		assertNotNull(session.getLastRemoteMessageId());
-		assertTrue(leaveMessage.getPreviousMessageId()
+		assertEquals(leaveMessage.getPreviousMessageId(),
-				.equals(session.getLastRemoteMessageId()));
+				session.getLastRemoteMessageId());
 
 		expectSetPrivateGroupVisibility(VISIBLE); // FIXME correct?
 		PeerSession newSession =
@@ -685,14 +695,14 @@ public class PeerProtocolEngineTest extends AbstractProtocolEngineTest {
 	}
 
 	private void assertSessionAborted(PeerSession oldSession,
-			PeerSession newSession) throws Exception {
+			PeerSession newSession) {
 		assertEquals(ERROR, newSession.getState());
 		assertSessionRecordedSentMessage(newSession);
 		assertSessionConstantsUnchanged(oldSession, newSession);
 	}
 
 	@Override
-	protected void assertSessionRecordedSentMessage(Session s) {
+	protected void assertSessionRecordedSentMessage(Session<?> s) {
 		assertEquals(messageId, s.getLastLocalMessageId());
 		assertEquals(lastRemoteMessageId, s.getLastRemoteMessageId());
 		assertEquals(messageTimestamp, s.getLocalTimestamp());