Parallel execution of tests

Question

I've noticed that SBT is running my specs2 tests in parallel. This seems good, except one of my tests involves reading and writing from a file and hence fails unpredictably, e.g. see below.

Are there any better options than

1. setting all tests to run in serial,
2. using separate file names and tear-downs for each test?

class WriteAndReadSpec extends Specification{
  val file = new File("testFiles/tmp.txt")

  "WriteAndRead" should {
    "work once" in {
      new FileWriter(file, false).append("Foo").close
      Source.fromFile(file).getLines().toList(0) must_== "Foo"
    }
    "work twice" in {
      new FileWriter(file, false).append("Bar").close
      Source.fromFile(file).getLines().toList(0) must_== "Bar"
    }
  }

  trait TearDown extends After {
    def after = if(file.exists) file.delete
  }
}

Answer 1

In addition to that is written about sbt above, you must know that specs2 runs all the examples of your specifications concurrently by default.

You can still declare that, for a given specification, the examples must be executed sequentially. To do that, you simply add sequential to the beginning of your specification:

class WriteAndReadSpec extends Specification{
  val file = new File("testFiles/tmp.txt")

  sequential

  "WriteAndRead" should {
   ...
  }
}