Add unit tests for migration logic.

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -68,7 +68,8 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 @NotNullByDefault
 abstract class JdbcDatabase implements Database<Connection> {
 
-	private static final int CODE_SCHEMA_VERSION = 33;
+	// Package access for testing
+	static final int CODE_SCHEMA_VERSION = 33;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
@@ -323,6 +324,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private boolean checkSchemaVersion(Connection txn) throws DbException {
 		Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
 		int dataSchemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
+		if (dataSchemaVersion == -1) return false;
 		if (dataSchemaVersion == CODE_SCHEMA_VERSION) return true;
 		if (CODE_SCHEMA_VERSION < dataSchemaVersion) return false;
 		// Do we have a suitable migration?
@@ -342,7 +344,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		return false;
 	}
 
-	private Collection<Migration<Connection>> getMigrations() {
+	// Package access for testing
+	Collection<Migration<Connection>> getMigrations() {
 		return Collections.emptyList();
 	}
 

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseMigrationTest.java

@@ -0,0 +1,183 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.system.SystemClock;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.TestDatabaseConfig;
+import org.briarproject.bramble.test.TestUtils;
+import org.jmock.Expectations;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.sql.Connection;
+import java.util.Collection;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
+import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
+import static org.briarproject.bramble.db.JdbcDatabase.CODE_SCHEMA_VERSION;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+@NotNullByDefault
+public abstract class DatabaseMigrationTest extends BrambleMockTestCase {
+
+	private final File testDir = TestUtils.getTestDirectory();
+	@SuppressWarnings("unchecked")
+	private final Migration<Connection> migration =
+			context.mock(Migration.class);
+
+	protected final DatabaseConfig config =
+			new TestDatabaseConfig(testDir, 1024 * 1024);
+	protected final Clock clock = new SystemClock();
+
+	abstract Database<Connection> createDatabase(
+			Collection<Migration<Connection>> migrations) throws Exception;
+
+	@Before
+	public void setUp() {
+		assertTrue(testDir.mkdirs());
+	}
+
+	@After
+	public void tearDown() {
+		TestUtils.deleteTestDirectory(testDir);
+	}
+
+	@Test
+	public void testDoesNotRunMigrationsWhenCreatingDatabase()
+			throws Exception {
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfDataSchemaVersionIsMissing()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, -1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(singletonList(migration));
+		db.open();
+	}
+
+	@Test
+	public void testDoesNotRunMigrationsIfSchemaVersionsMatch()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+		// Reopen the DB - migrations should not be run
+		db = createDatabase(singletonList(migration));
+		assertTrue(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfDataIsNewerThanCode() throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION + 1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(singletonList(migration));
+		db.open();
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfCodeIsNewerThanDataAndNoMigrations()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(emptyList());
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(emptyList());
+		db.open();
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfCodeIsNewerThanDataAndNoSuitableMigration()
+			throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(migration).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 2));
+			oneOf(migration).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+		}});
+
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(singletonList(migration));
+		db.open();
+	}
+
+	@Test
+	public void testRunsMigrationIfCodeIsNewerThanDataAndSuitableMigration()
+			throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(migration).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+			oneOf(migration).migrate(with(any(Connection.class)));
+		}});
+
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 1);
+		db.close();
+		// Reopen the DB - the migration should be run
+		db = createDatabase(singletonList(migration));
+		assertTrue(db.open());
+		db.close();
+	}
+
+	private int getDataSchemaVersion(Database<Connection> db)
+			throws Exception {
+		Connection txn = db.startTransaction();
+		Settings s = db.getSettings(txn, DB_SETTINGS_NAMESPACE);
+		db.commitTransaction(txn);
+		return s.getInt(SCHEMA_VERSION_KEY, -1);
+	}
+
+	private void setDataSchemaVersion(Database<Connection> db, int version)
+			throws Exception {
+		Settings s = new Settings();
+		s.putInt(SCHEMA_VERSION_KEY, version);
+		Connection txn = db.startTransaction();
+		db.mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
+		db.commitTransaction(txn);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/H2MigrationTest.java

@@ -0,0 +1,21 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.sql.Connection;
+import java.util.Collection;
+
+@NotNullByDefault
+public class H2MigrationTest extends DatabaseMigrationTest {
+
+	@Override
+	Database<Connection> createDatabase(
+			Collection<Migration<Connection>> migrations) throws Exception {
+		return new H2Database(config, clock) {
+			@Override
+			Collection<Migration<Connection>> getMigrations() {
+				return migrations;
+			}
+		};
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/HyperSqlMigrationTest.java

@@ -0,0 +1,21 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.sql.Connection;
+import java.util.Collection;
+
+@NotNullByDefault
+public class HyperSqlMigrationTest extends DatabaseMigrationTest {
+
+	@Override
+	Database<Connection> createDatabase(
+			Collection<Migration<Connection>> migrations) throws Exception {
+		return new HyperSqlDatabase(config, clock) {
+			@Override
+			Collection<Migration<Connection>> getMigrations() {
+				return migrations;
+			}
+		};
+	}
+}