sbt-revolver | SBT plugin for dangerously fast development turnaround | Build Tool library

fork doesn't run task in parallel - it just makes sure that tests are run in a separate JVM which helps with things like shutdown webhooks or disconnecting from services that doesn't handle resource release properly (e.g. DB connection that never calls disconnect).

If you want to use the same sbt to start server AND run test against that instance (which sounds like easily breakable antipattern BTW) you can use somethings like:

• reStart
• it:test
• reStop

However that would be tricky because reStart yields immediately so tests would start when the server setup started but not necessarily completed. Race condition, failing tests, or blocking all tests until server finishes starting.

This is why nobody does it. Much easier to handle solution is to:

• start the server in test in some beforeAll method and make this method complete only after server is responding to queries
• shutdown it in some afterAll method (or somehow handle both of these using something like cats.effect.Resource or similar)
• depending on situation:
  • running tests sequentially to avoid starting two instances at the same time or
  • generating config for each test so that they could be run in parallel without clashing on ports allocations

Anything else is just a hack that is going to fail sooner rather than later.