For separating integration tests, from unit tests, in build.sbt:

// sbt command-line shortcut
addCommandAlias("ci-integration", "Integration/testOnly -- -n integrationTest")

lazy val IntegrationTest = config("integration").extend(Test)

//...
lazy val root = Project(base = file("."))
  .configs(IntegrationTest)
  .settings(
    // Exclude integration tests by default (in ScalaTest)
    Test / testOptions += Tests.Argument(TestFrameworks.ScalaTest, "-l", "integrationTest"),
    // Include integration tests, by nullifying the above option
    IntegrationTest / testOptions := Seq.empty,
  )
  .settings(
    // Enable integration tests
    inConfig(IntegrationTest)(Defaults.testTasks)
  )

Then in your tests:

import org.scalatest.Tag
import org.scalatest.funsuite.AsyncFunSuite

object IntegrationTest extends Tag("integrationTest")

class MyTestSuite extends AsyncFunSuite {
  // Tagging this test as an integration test
  test("integration works", IntegrationTest) {
    ???
  }
}

Then run:

sbt ci-integration