The default behavior for ScalaTest is to "run different suites in parallel, but the tests of any one suite sequentially." See ParallelTestExecution.
How do I constrain a set of Suites, maybe using a SuiteMixin, to all run sequentially? This related answer says to "enable forking but disable parallel execution." How do I do this with the gradle test runner?
My use case is specifically around running a set of SparkSession based integration test suites under gradle.