Speed up postgresql container without initing everytime

A newly created postgresql container will do a following steps. They are quite time consuming in integration testing and add some unpredictable factor. If a integration testing will clean up tables and data, volumes can be used to speed up postgresql container.

There might be one issue, do I need to maintain the same credential? need to further explore on this. So far my manully created container bind-mounted to the same volumes can be accessed and no tables in it after running integration test.