package org.briarproject.db;

import org.briarproject.BriarTestCase;
import org.briarproject.TestUtils;
import org.briarproject.api.TransportId;
import org.briarproject.api.contact.Contact;
import org.briarproject.api.contact.ContactId;
import org.briarproject.api.crypto.SecretKey;
import org.briarproject.api.db.DatabaseComponent;
import org.briarproject.api.db.Metadata;
import org.briarproject.api.db.NoSuchContactException;
import org.briarproject.api.db.NoSuchGroupException;
import org.briarproject.api.db.NoSuchLocalAuthorException;
import org.briarproject.api.db.NoSuchMessageException;
import org.briarproject.api.db.NoSuchTransportException;
import org.briarproject.api.db.Transaction;
import org.briarproject.api.event.ContactAddedEvent;
import org.briarproject.api.event.ContactRemovedEvent;
import org.briarproject.api.event.ContactStatusChangedEvent;
import org.briarproject.api.event.EventBus;
import org.briarproject.api.event.GroupAddedEvent;
import org.briarproject.api.event.GroupRemovedEvent;
import org.briarproject.api.event.GroupVisibilityUpdatedEvent;
import org.briarproject.api.event.LocalAuthorAddedEvent;
import org.briarproject.api.event.LocalAuthorRemovedEvent;
import org.briarproject.api.event.MessageAddedEvent;
import org.briarproject.api.event.MessageRequestedEvent;
import org.briarproject.api.event.MessageSharedEvent;
import org.briarproject.api.event.MessageToAckEvent;
import org.briarproject.api.event.MessageToRequestEvent;
import org.briarproject.api.event.MessageValidatedEvent;
import org.briarproject.api.event.MessagesAckedEvent;
import org.briarproject.api.event.MessagesSentEvent;
import org.briarproject.api.event.SettingsUpdatedEvent;
import org.briarproject.api.identity.Author;
import org.briarproject.api.identity.AuthorId;
import org.briarproject.api.identity.LocalAuthor;
import org.briarproject.api.lifecycle.ShutdownManager;
import org.briarproject.api.settings.Settings;
import org.briarproject.api.sync.Ack;
import org.briarproject.api.sync.ClientId;
import org.briarproject.api.sync.Group;
import org.briarproject.api.sync.GroupId;
import org.briarproject.api.sync.Message;
import org.briarproject.api.sync.MessageId;
import org.briarproject.api.sync.Offer;
import org.briarproject.api.sync.Request;
import org.briarproject.api.transport.IncomingKeys;
import org.briarproject.api.transport.OutgoingKeys;
import org.briarproject.api.transport.TransportKeys;
import org.jmock.Expectations;
import org.jmock.Mockery;
import org.junit.Test;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;

import static org.briarproject.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
import static org.briarproject.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
import static org.briarproject.api.sync.ValidationManager.Validity.UNKNOWN;
import static org.briarproject.api.sync.ValidationManager.Validity.VALID;
import static org.briarproject.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
import static org.briarproject.db.DatabaseConstants.MAX_OFFERED_MESSAGES;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.fail;

public class DatabaseComponentImplTest extends BriarTestCase {

	private final Object txn = new Object();
	private final ClientId clientId;
	private final GroupId groupId;
	private final Group group;
	private final AuthorId authorId;
	private final Author author;
	private final AuthorId localAuthorId;
	private final LocalAuthor localAuthor;
	private final MessageId messageId, messageId1;
	private final int size;
	private final byte[] raw;
	private final Message message;
	private final Metadata metadata;
	private final TransportId transportId;
	private final int maxLatency;
	private final ContactId contactId;
	private final Contact contact;

	public DatabaseComponentImplTest() {
		clientId = new ClientId(TestUtils.getRandomId());
		groupId = new GroupId(TestUtils.getRandomId());
		byte[] descriptor = new byte[MAX_GROUP_DESCRIPTOR_LENGTH];
		group = new Group(groupId, clientId, descriptor);
		authorId = new AuthorId(TestUtils.getRandomId());
		author = new Author(authorId, "Alice", new byte[MAX_PUBLIC_KEY_LENGTH]);
		localAuthorId = new AuthorId(TestUtils.getRandomId());
		long timestamp = System.currentTimeMillis();
		localAuthor = new LocalAuthor(localAuthorId, "Bob",
				new byte[MAX_PUBLIC_KEY_LENGTH], new byte[123], timestamp);
		messageId = new MessageId(TestUtils.getRandomId());
		messageId1 = new MessageId(TestUtils.getRandomId());
		size = 1234;
		raw = new byte[size];
		message = new Message(messageId, groupId, timestamp, raw);
		metadata = new Metadata();
		metadata.put("foo", new byte[] {'b', 'a', 'r'});
		transportId = new TransportId("id");
		maxLatency = Integer.MAX_VALUE;
		contactId = new ContactId(234);
		contact = new Contact(contactId, author, localAuthorId, true);
	}

	private DatabaseComponent createDatabaseComponent(Database<Object> database,
			EventBus eventBus, ShutdownManager shutdown) {
		return new DatabaseComponentImpl<Object>(database, Object.class,
				eventBus, shutdown);
	}

	@Test
	@SuppressWarnings("unchecked")
	public void testSimpleCalls() throws Exception {
		final int shutdownHandle = 12345;
		Mockery context = new Mockery();
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// open()
			oneOf(database).open();
			will(returnValue(false));
			oneOf(shutdown).addShutdownHook(with(any(Runnable.class)));
			will(returnValue(shutdownHandle));
			// startTransaction()
			oneOf(database).startTransaction();
			will(returnValue(txn));
			// addLocalAuthor()
			oneOf(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(false));
			oneOf(database).addLocalAuthor(txn, localAuthor);
			oneOf(eventBus).broadcast(with(any(LocalAuthorAddedEvent.class)));
			// addContact()
			oneOf(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(true));
			oneOf(database).containsContact(txn, authorId, localAuthorId);
			will(returnValue(false));
			oneOf(database).addContact(txn, author, localAuthorId, true);
			will(returnValue(contactId));
			oneOf(eventBus).broadcast(with(any(ContactAddedEvent.class)));
			oneOf(eventBus).broadcast(with(any(
					ContactStatusChangedEvent.class)));
			// getContacts()
			oneOf(database).getContacts(txn);
			will(returnValue(Collections.singletonList(contact)));
			// addGroup()
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(false));
			oneOf(database).addGroup(txn, group);
			oneOf(eventBus).broadcast(with(any(GroupAddedEvent.class)));
			// addGroup() again
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(true));
			// getGroups()
			oneOf(database).getGroups(txn, clientId);
			will(returnValue(Collections.singletonList(group)));
			// removeGroup()
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(true));
			oneOf(database).getVisibility(txn, groupId);
			will(returnValue(Collections.emptyList()));
			oneOf(database).removeGroup(txn, groupId);
			oneOf(eventBus).broadcast(with(any(GroupRemovedEvent.class)));
			oneOf(eventBus).broadcast(with(any(
					GroupVisibilityUpdatedEvent.class)));
			// removeContact()
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).removeContact(txn, contactId);
			oneOf(eventBus).broadcast(with(any(ContactRemovedEvent.class)));
			// removeLocalAuthor()
			oneOf(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(true));
			oneOf(database).removeLocalAuthor(txn, localAuthorId);
			oneOf(eventBus).broadcast(with(any(LocalAuthorRemovedEvent.class)));
			// endTransaction()
			oneOf(database).commitTransaction(txn);
			// close()
			oneOf(shutdown).removeShutdownHook(shutdownHandle);
			oneOf(database).close();
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		assertFalse(db.open());
		Transaction transaction = db.startTransaction(false);
		try {
			db.addLocalAuthor(transaction, localAuthor);
			assertEquals(contactId,
					db.addContact(transaction, author, localAuthorId, true));
			assertEquals(Collections.singletonList(contact),
					db.getContacts(transaction));
			db.addGroup(transaction, group); // First time - listeners called
			db.addGroup(transaction, group); // Second time - not called
			assertEquals(Collections.singletonList(group),
					db.getGroups(transaction, clientId));
			db.removeGroup(transaction, group);
			db.removeContact(transaction, contactId);
			db.removeLocalAuthor(transaction, localAuthorId);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}
		db.close();

		context.assertIsSatisfied();
	}

	@Test
	public void testLocalMessagesAreNotStoredUnlessGroupExists()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(false));
			oneOf(database).abortTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.addLocalMessage(transaction, message, clientId, metadata, true);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testAddLocalMessage() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(true));
			oneOf(database).containsMessage(txn, messageId);
			will(returnValue(false));
			oneOf(database).addMessage(txn, message, VALID, true);
			oneOf(database).mergeMessageMetadata(txn, messageId, metadata);
			oneOf(database).getVisibility(txn, groupId);
			will(returnValue(Collections.singletonList(contactId)));
			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
			will(returnValue(false));
			oneOf(database).addStatus(txn, contactId, messageId, false, false);
			oneOf(database).commitTransaction(txn);
			// The message was added, so the listeners should be called
			oneOf(eventBus).broadcast(with(any(MessageAddedEvent.class)));
			oneOf(eventBus).broadcast(with(any(MessageValidatedEvent.class)));
			oneOf(eventBus).broadcast(with(any(MessageSharedEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.addLocalMessage(transaction, message, clientId, metadata, true);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testVariousMethodsThrowExceptionIfContactIsMissing()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// Check whether the contact is in the DB (which it's not)
			exactly(18).of(database).startTransaction();
			will(returnValue(txn));
			exactly(18).of(database).containsContact(txn, contactId);
			will(returnValue(false));
			exactly(18).of(database).abortTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.addTransportKeys(transaction, contactId, createTransportKeys());
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.generateAck(transaction, contactId, 123);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.generateBatch(transaction, contactId, 123, 456);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.generateOffer(transaction, contactId, 123, 456);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.generateRequest(transaction, contactId, 123);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getContact(transaction, contactId);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getMessageStatus(transaction, contactId, groupId);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getMessageStatus(transaction, contactId, messageId);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.incrementStreamCounter(transaction, contactId, transportId, 0);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.isVisibleToContact(transaction, contactId, groupId);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			Ack a = new Ack(Collections.singletonList(messageId));
			db.receiveAck(transaction, contactId, a);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.receiveMessage(transaction, contactId, message);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			Offer o = new Offer(Collections.singletonList(messageId));
			db.receiveOffer(transaction, contactId, o);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			Request r = new Request(Collections.singletonList(messageId));
			db.receiveRequest(transaction, contactId, r);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.removeContact(transaction, contactId);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setContactActive(transaction, contactId, true);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setReorderingWindow(transaction, contactId, transportId, 0, 0,
					new byte[REORDERING_WINDOW_SIZE / 8]);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setVisibleToContact(transaction, contactId, groupId, true);
			fail();
		} catch (NoSuchContactException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testVariousMethodsThrowExceptionIfLocalAuthorIsMissing()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// Check whether the pseudonym is in the DB (which it's not)
			exactly(3).of(database).startTransaction();
			will(returnValue(txn));
			exactly(3).of(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(false));
			exactly(3).of(database).abortTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.addContact(transaction, author, localAuthorId, true);
			fail();
		} catch (NoSuchLocalAuthorException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getLocalAuthor(transaction, localAuthorId);
			fail();
		} catch (NoSuchLocalAuthorException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.removeLocalAuthor(transaction, localAuthorId);
			fail();
		} catch (NoSuchLocalAuthorException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testVariousMethodsThrowExceptionIfGroupIsMissing()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// Check whether the group is in the DB (which it's not)
			exactly(7).of(database).startTransaction();
			will(returnValue(txn));
			exactly(7).of(database).containsGroup(txn, groupId);
			will(returnValue(false));
			exactly(7).of(database).abortTransaction(txn);
			// This is needed for getMessageStatus(), isVisibleToContact(), and
			// setVisibleToContact() to proceed
			exactly(3).of(database).containsContact(txn, contactId);
			will(returnValue(true));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.getGroup(transaction, groupId);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getGroupMetadata(transaction, groupId);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getMessageStatus(transaction, contactId, groupId);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.isVisibleToContact(transaction, contactId, groupId);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.mergeGroupMetadata(transaction, groupId, metadata);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.removeGroup(transaction, group);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setVisibleToContact(transaction, contactId, groupId, true);
			fail();
		} catch (NoSuchGroupException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testVariousMethodsThrowExceptionIfMessageIsMissing()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// Check whether the message is in the DB (which it's not)
			exactly(8).of(database).startTransaction();
			will(returnValue(txn));
			exactly(8).of(database).containsMessage(txn, messageId);
			will(returnValue(false));
			exactly(8).of(database).abortTransaction(txn);
			// This is needed for getMessageStatus() to proceed
			exactly(1).of(database).containsContact(txn, contactId);
			will(returnValue(true));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.deleteMessage(transaction, messageId);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.deleteMessageMetadata(transaction, messageId);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getRawMessage(transaction, messageId);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getMessageMetadata(transaction, messageId);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getMessageStatus(transaction, contactId, messageId);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.mergeMessageMetadata(transaction, messageId, metadata);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setMessageShared(transaction, message, true);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setMessageValid(transaction, message, clientId, true);
			fail();
		} catch (NoSuchMessageException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testVariousMethodsThrowExceptionIfTransportIsMissing()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// startTransaction()
			oneOf(database).startTransaction();
			will(returnValue(txn));
			// addLocalAuthor()
			oneOf(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(false));
			oneOf(database).addLocalAuthor(txn, localAuthor);
			oneOf(eventBus).broadcast(with(any(LocalAuthorAddedEvent.class)));
			// addContact()
			oneOf(database).containsLocalAuthor(txn, localAuthorId);
			will(returnValue(true));
			oneOf(database).containsContact(txn, authorId, localAuthorId);
			will(returnValue(false));
			oneOf(database).addContact(txn, author, localAuthorId, true);
			will(returnValue(contactId));
			oneOf(eventBus).broadcast(with(any(ContactAddedEvent.class)));
			oneOf(eventBus).broadcast(with(any(
					ContactStatusChangedEvent.class)));
			// endTransaction()
			oneOf(database).commitTransaction(txn);
			// Check whether the transport is in the DB (which it's not)
			exactly(4).of(database).startTransaction();
			will(returnValue(txn));
			exactly(2).of(database).containsContact(txn, contactId);
			will(returnValue(true));
			exactly(4).of(database).containsTransport(txn, transportId);
			will(returnValue(false));
			exactly(4).of(database).abortTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.addLocalAuthor(transaction, localAuthor);
			assertEquals(contactId,
					db.addContact(transaction, author, localAuthorId, true));
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.getTransportKeys(transaction, transportId);
			fail();
		} catch (NoSuchTransportException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.incrementStreamCounter(transaction, contactId, transportId, 0);
			fail();
		} catch (NoSuchTransportException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.removeTransport(transaction, transportId);
			fail();
		} catch (NoSuchTransportException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		transaction = db.startTransaction(false);
		try {
			db.setReorderingWindow(transaction, contactId, transportId, 0, 0,
					new byte[REORDERING_WINDOW_SIZE / 8]);
			fail();
		} catch (NoSuchTransportException expected) {
			// Expected
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testGenerateAck() throws Exception {
		final Collection<MessageId> messagesToAck = Arrays.asList(messageId,
				messageId1);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).getMessagesToAck(txn, contactId, 123);
			will(returnValue(messagesToAck));
			oneOf(database).lowerAckFlag(txn, contactId, messagesToAck);
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Ack a = db.generateAck(transaction, contactId, 123);
			assertEquals(messagesToAck, a.getMessageIds());
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testGenerateBatch() throws Exception {
		final byte[] raw1 = new byte[size];
		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
		final Collection<byte[]> messages = Arrays.asList(raw, raw1);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).getMessagesToSend(txn, contactId, size * 2);
			will(returnValue(ids));
			oneOf(database).getRawMessage(txn, messageId);
			will(returnValue(raw));
			oneOf(database).updateExpiryTime(txn, contactId, messageId,
					maxLatency);
			oneOf(database).getRawMessage(txn, messageId1);
			will(returnValue(raw1));
			oneOf(database).updateExpiryTime(txn, contactId, messageId1,
					maxLatency);
			oneOf(database).lowerRequestedFlag(txn, contactId, ids);
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(MessagesSentEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			assertEquals(messages, db.generateBatch(transaction, contactId,
					size * 2, maxLatency));
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testGenerateOffer() throws Exception {
		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).getMessagesToOffer(txn, contactId, 123);
			will(returnValue(ids));
			oneOf(database).updateExpiryTime(txn, contactId, messageId,
					maxLatency);
			oneOf(database).updateExpiryTime(txn, contactId, messageId1,
					maxLatency);
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Offer o = db.generateOffer(transaction, contactId, 123, maxLatency);
			assertEquals(ids, o.getMessageIds());
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testGenerateRequest() throws Exception {
		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).getMessagesToRequest(txn, contactId, 123);
			will(returnValue(ids));
			oneOf(database).removeOfferedMessages(txn, contactId, ids);
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Request r = db.generateRequest(transaction, contactId, 123);
			assertEquals(ids, r.getMessageIds());
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testGenerateRequestedBatch() throws Exception {
		final byte[] raw1 = new byte[size];
		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
		final Collection<byte[]> messages = Arrays.asList(raw, raw1);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).getRequestedMessagesToSend(txn, contactId,
					size * 2);
			will(returnValue(ids));
			oneOf(database).getRawMessage(txn, messageId);
			will(returnValue(raw));
			oneOf(database).updateExpiryTime(txn, contactId, messageId,
					maxLatency);
			oneOf(database).getRawMessage(txn, messageId1);
			will(returnValue(raw1));
			oneOf(database).updateExpiryTime(txn, contactId, messageId1,
					maxLatency);
			oneOf(database).lowerRequestedFlag(txn, contactId, ids);
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(MessagesSentEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			assertEquals(messages, db.generateRequestedBatch(transaction,
					contactId, size * 2, maxLatency));
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveAck() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
			will(returnValue(true));
			oneOf(database).raiseSeenFlag(txn, contactId, messageId);
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(MessagesAckedEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Ack a = new Ack(Collections.singletonList(messageId));
			db.receiveAck(transaction, contactId, a);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveMessage() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsMessage(txn, messageId);
			will(returnValue(false));
			oneOf(database).containsVisibleGroup(txn, contactId, groupId);
			will(returnValue(true));
			oneOf(database).addMessage(txn, message, UNKNOWN, false);
			oneOf(database).getVisibility(txn, groupId);
			will(returnValue(Collections.singletonList(contactId)));
			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
			will(returnValue(false));
			oneOf(database).addStatus(txn, contactId, messageId, false, false);
			oneOf(database).raiseAckFlag(txn, contactId, messageId);
			oneOf(database).commitTransaction(txn);
			// The message was received and added
			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
			oneOf(eventBus).broadcast(with(any(MessageAddedEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.receiveMessage(transaction, contactId, message);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveDuplicateMessage() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsMessage(txn, messageId);
			will(returnValue(true));
			oneOf(database).containsVisibleGroup(txn, contactId, groupId);
			will(returnValue(true));
			// The message wasn't stored but it must still be acked
			oneOf(database).raiseAckFlag(txn, contactId, messageId);
			oneOf(database).commitTransaction(txn);
			// The message was received but not added
			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.receiveMessage(transaction, contactId, message);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveMessageWithoutVisibleGroup() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsVisibleGroup(txn, contactId, groupId);
			will(returnValue(false));
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.receiveMessage(transaction, contactId, message);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveOffer() throws Exception {
		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
		final MessageId messageId2 = new MessageId(TestUtils.getRandomId());
		final MessageId messageId3 = new MessageId(TestUtils.getRandomId());
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			// There's room for two more offered messages
			oneOf(database).countOfferedMessages(txn, contactId);
			will(returnValue(MAX_OFFERED_MESSAGES - 2));
			// The first message isn't visible - request it
			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
			will(returnValue(false));
			oneOf(database).addOfferedMessage(txn, contactId, messageId);
			// The second message is visible - ack it
			oneOf(database).containsVisibleMessage(txn, contactId, messageId1);
			will(returnValue(true));
			oneOf(database).raiseSeenFlag(txn, contactId, messageId1);
			oneOf(database).raiseAckFlag(txn, contactId, messageId1);
			// The third message isn't visible - request it
			oneOf(database).containsVisibleMessage(txn, contactId, messageId2);
			will(returnValue(false));
			oneOf(database).addOfferedMessage(txn, contactId, messageId2);
			// The fourth message isn't visible, but there's no room to store it
			oneOf(database).containsVisibleMessage(txn, contactId, messageId3);
			will(returnValue(false));
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
			oneOf(eventBus).broadcast(with(any(MessageToRequestEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Offer o = new Offer(Arrays.asList(messageId, messageId1,
					messageId2, messageId3));
			db.receiveOffer(transaction, contactId, o);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testReceiveRequest() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
			will(returnValue(true));
			oneOf(database).raiseRequestedFlag(txn, contactId, messageId);
			oneOf(database).resetExpiryTime(txn, contactId, messageId);
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(MessageRequestedEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			Request r = new Request(Collections.singletonList(messageId));
			db.receiveRequest(transaction, contactId, r);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testChangingVisibilityCallsListeners() throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(true));
			oneOf(database).containsVisibleGroup(txn, contactId, groupId);
			will(returnValue(false)); // Not yet visible
			oneOf(database).addVisibility(txn, contactId, groupId);
			oneOf(database).getMessageIds(txn, groupId);
			will(returnValue(Collections.singletonList(messageId)));
			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
			will(returnValue(false));
			oneOf(database).addStatus(txn, contactId, messageId, false, false);
			oneOf(database).commitTransaction(txn);
			oneOf(eventBus).broadcast(with(any(
					GroupVisibilityUpdatedEvent.class)));
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.setVisibleToContact(transaction, contactId, groupId, true);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testNotChangingVisibilityDoesNotCallListeners()
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(txn));
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsGroup(txn, groupId);
			will(returnValue(true));
			oneOf(database).containsVisibleGroup(txn, contactId, groupId);
			will(returnValue(true)); // Already visible
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.setVisibleToContact(transaction, contactId, groupId, true);
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test
	public void testTransportKeys() throws Exception {
		final TransportKeys transportKeys = createTransportKeys();
		final Map<ContactId, TransportKeys> keys = Collections.singletonMap(
				contactId, transportKeys);
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// startTransaction()
			oneOf(database).startTransaction();
			will(returnValue(txn));
			// updateTransportKeys()
			oneOf(database).containsContact(txn, contactId);
			will(returnValue(true));
			oneOf(database).containsTransport(txn, transportId);
			will(returnValue(true));
			oneOf(database).updateTransportKeys(txn, keys);
			// getTransportKeys()
			oneOf(database).containsTransport(txn, transportId);
			will(returnValue(true));
			oneOf(database).getTransportKeys(txn, transportId);
			will(returnValue(keys));
			// endTransaction()
			oneOf(database).commitTransaction(txn);
		}});
		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			db.updateTransportKeys(transaction, keys);
			assertEquals(keys, db.getTransportKeys(transaction, transportId));
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	private TransportKeys createTransportKeys() {
		SecretKey inPrevTagKey = TestUtils.getSecretKey();
		SecretKey inPrevHeaderKey = TestUtils.getSecretKey();
		IncomingKeys inPrev = new IncomingKeys(inPrevTagKey, inPrevHeaderKey,
				1, 123, new byte[4]);
		SecretKey inCurrTagKey = TestUtils.getSecretKey();
		SecretKey inCurrHeaderKey = TestUtils.getSecretKey();
		IncomingKeys inCurr = new IncomingKeys(inCurrTagKey, inCurrHeaderKey,
				2, 234, new byte[4]);
		SecretKey inNextTagKey = TestUtils.getSecretKey();
		SecretKey inNextHeaderKey = TestUtils.getSecretKey();
		IncomingKeys inNext = new IncomingKeys(inNextTagKey, inNextHeaderKey,
				3, 345, new byte[4]);
		SecretKey outCurrTagKey = TestUtils.getSecretKey();
		SecretKey outCurrHeaderKey = TestUtils.getSecretKey();
		OutgoingKeys outCurr = new OutgoingKeys(outCurrTagKey, outCurrHeaderKey,
				2, 456);
		return new TransportKeys(transportId, inPrev, inCurr, inNext, outCurr);
	}

	@Test
	public void testMergeSettings() throws Exception {
		final Settings before = new Settings();
		before.put("foo", "bar");
		before.put("baz", "bam");
		final Settings update = new Settings();
		update.put("baz", "qux");
		final Settings merged = new Settings();
		merged.put("foo", "bar");
		merged.put("baz", "qux");
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);
		context.checking(new Expectations() {{
			// startTransaction()
			oneOf(database).startTransaction();
			will(returnValue(txn));
			// mergeSettings()
			oneOf(database).getSettings(txn, "namespace");
			will(returnValue(before));
			oneOf(database).mergeSettings(txn, update, "namespace");
			oneOf(eventBus).broadcast(with(any(SettingsUpdatedEvent.class)));
			// mergeSettings() again
			oneOf(database).getSettings(txn, "namespace");
			will(returnValue(merged));
			// endTransaction()
			oneOf(database).commitTransaction(txn);
		}});

		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		Transaction transaction = db.startTransaction(false);
		try {
			// First merge should broadcast an event
			db.mergeSettings(transaction, update, "namespace");
			// Second merge should not broadcast an event
			db.mergeSettings(transaction, update, "namespace");
			transaction.setComplete();
		} finally {
			db.endTransaction(transaction);
		}

		context.assertIsSatisfied();
	}

	@Test(expected = IllegalStateException.class)
	public void testCannotStartReadTransactionDuringReadTransaction()
			throws Exception {
		testCannotStartTransactionDuringTransaction(true, true);
	}

	@Test(expected = IllegalStateException.class)
	public void testCannotStartWriteTransactionDuringReadTransaction()
			throws Exception {
		testCannotStartTransactionDuringTransaction(true, false);
	}

	@Test(expected = IllegalStateException.class)
	public void testCannotStartReadTransactionDuringWriteTransaction()
			throws Exception {
		testCannotStartTransactionDuringTransaction(false, true);
	}

	@Test(expected = IllegalStateException.class)
	public void testCannotStartWriteTransactionDuringWriteTransaction()
			throws Exception {
		testCannotStartTransactionDuringTransaction(false, false);
	}

	private void testCannotStartTransactionDuringTransaction(
			boolean firstTxnReadOnly, boolean secondTxnReadOnly)
			throws Exception {
		Mockery context = new Mockery();
		@SuppressWarnings("unchecked")
		final Database<Object> database = context.mock(Database.class);
		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
		final EventBus eventBus = context.mock(EventBus.class);

		context.checking(new Expectations() {{
			oneOf(database).startTransaction();
			will(returnValue(new Object()));
		}});

		DatabaseComponent db = createDatabaseComponent(database, eventBus,
				shutdown);

		assertNotNull(db.startTransaction(firstTxnReadOnly));
		try {
			db.startTransaction(secondTxnReadOnly);
		} finally {
			context.assertIsSatisfied();
		}
	}
}