     func testPersistentWALModeEnabled() throws {
         let path: String
         do {
-            var configuration = dbConfiguration!
-            configuration.prepareDatabase = { db in
+            dbConfiguration.prepareDatabase = { db in
                 var flag: CInt = 1
                 let code = withUnsafeMutablePointer(to: &flag) { flagP in
                     sqlite3_file_control(db.sqliteConnection, nil, SQLITE_FCNTL_PERSIST_WAL, flagP)

    func testPersistentWALModeDisabled() throws {
        let path: String
        do {
            var configuration = dbConfiguration!
            configuration.prepareDatabase = { db in
                var flag: CInt = 0
                let code = withUnsafeMutablePointer(to: &flag) { flagP in
                    sqlite3_file_control(db.sqliteConnection, nil, SQLITE_FCNTL_PERSIST_WAL, flagP)

        XCTAssertFalse(fm.fileExists(atPath: path + "-wal"))
        XCTAssertFalse(fm.fileExists(atPath: path + "-shm"))
    }
}
