Can I get the name of a test?

[oharboe]

I am using Chisel from Bazel and I need to pass the name of the folder into which the simulation files should be written to ChiselSim.

Is there a way to avoid the duplicated code below to pass testName into the .simulate() call:

it should "Iffy loop" in {
    mysim.simulate(module = new FooTestBench(), testName = "Iffy loop") { dut =>
      ResetProcedure.module(10)(dut)
      RunUntilFinished(maxCycles = 1000)(dut)
    }
  }

[seldridge]

It looks like this is a non-standard simulate method?

You may want to look at how ChiselSim handles this for it's normal simulate methods. This takes a type class implementation of HasTestingDirectory. The actual implementation of HasTestingDirectory provided by scalatest.ChiselSim (implicit final def implementation in this trait:

chisel/src/main/scala/chisel3/testing/scalatest/WithTestingDirectory.scala

Line 11 in c4ca27e

/** A mix-in for a Scalatest test suite that will setup the output directory for

) uses a Scalatest fixture to examine all the scopes.

If you do something like that, you should be able to get this information. You may also be able to just use this as is and use implicitly[HasTestingDirectory] to get whatever the directory is. E.g., like this:

chisel/src/test/scala-2/chiselTests/SimLogSpec.scala

Line 109 in c4ca27e

val testdir = implicitly[HasTestingDirectory].getDirectory

[oharboe]

Yes, I'm using Bazel so I'm creating some creature comforts. The Chisel default implementaition is mill/sbt oriented(i.e. install things locally), whereas Bazel is oriented towards hermeticity.

[oharboe]

Will give it a try, this Scala stuff is pretty cryptic :-)

[oharboe]

testDir has an unsatisfying name... build/chiselsim/2025-07-23T05-15-35.559186410. For a good local workflow, I want the output dir to be stable in bazel, so that I can keep a .vcd file open for view in gtkwave/vscode surfer(hit 'r' to refresh).

If I add:

class MyTests extends AnyFlatSpec with TestingDirectory{
...
  it should "Simple loop" in {
...
    val testdir = implicitly[HasTestingDirectory].getDirectory
    println(s"Test directory: $testdir")

I get a more satisfying:

Test directory: [deleted]/should-Simple-loop

[oharboe]

If I modify my simulate implementation to take this as an implicit parameter, I'm in business 😌

  def simulate[T <: RawModule](
      module: => T,
      chiselSettings: Settings[T] = Settings.defaultRaw[T]
  )(body: (T) => Unit)(implicit testDir: HasTestingDirectory): Unit = {
    println(s"Test directory: ${testDir.getDirectory}")

Test directory: [deleted]/should-Simple-loop

[seldridge]

Sounds good.

The high level approach here is that there needs to be an implicit HasTestingDirectory available or passed explicitly. That has a low-priority default which will use timestamps. This is suitable for any environment, including those which aren't Scalatest.

If you are in a Scalatest environment, you can mix-in scalatest.TestingDirectory which will override the low-priority default and use the Scalatest scopes to provide a better name. If you are using the ChiselSim trait, you get this for free. If you are using something a bit different, then you need to do some more work, but the traits are all there.