[WatchDog]

So the alternative is to mock out every database call or use a full database to run the tests. Using an in-memory database is convenient, keeps your tests portable and most importantly it helps catch a lot of bugs that might of been missed with mocking. It might not be as good as using the real DB, but its better nothing.

[jeltz]

PostgreSQL will be close enough to an in memory database if you turn off synchronous_commit. For most test ssuties I would suspect much more time will be spent plannign the queries (which can be improved with prepared staatments) than the time spent on disk IO if you just reduce the durability requirements of your test database.

[lmz]

Data directory on tmpfs is close enough to an in-memory database.