SingleThreadSlickApi.scala

  protected [helpers] val singleSession = databaseConnection.createSession

  val noDataSource = new JdbcDataSource {
    def createConnection(): Connection = throw new RuntimeException("Tried to allocate another connection in test mode. This is an issue because the test database assumes that only one database connection in used. RolledbackDatabase needs to be improved.")
    def close(): Unit = ()
  }

  // backend.BaseSession
  class DelegatingSession(session: backend.SessionDef) extends backend.SessionDef {
    override def database = session.database
    override def conn = session.conn
    override def metaData = session.metaData
    override def capabilities = session.capabilities
    override def resultSetType = session.resultSetType
    override def resultSetConcurrency = session.resultSetConcurrency
    override def resultSetHoldability = session.resultSetHoldability
    override def fetchSize = session.fetchSize
    override def close() = session.close()
    override def rollback() = session.rollback()
    override def force() = session.force()
    override def withTransaction[T](f: => T) = session.withTransaction(f)
    override def asDynamicSession[T](f: => T): T = session.asDynamicSession(f)
    // These are private, so they won't be called directly. But, they need to be implemented.
    def endInTransaction(f: => Unit): Unit = ???
    def startInTransaction: Unit = ???
  }

  protected object SingleConnectionDatabase extends backend.DatabaseDef(noDataSource, AsyncExecutor("single-thread", 1, 1000)) {
    override def createSession(): backend.Session = {
      new DelegatingSession(singleSession) {
        override def close(): Unit = {
        }
      }
    }
  }