add tb folder

build.sbt

@@ -10,6 +10,7 @@ val spinalIdslPlugin = compilerPlugin("com.github.spinalhdl" %% "spinalhdl-idsl-
 lazy val projectname = (project in file("."))
   .settings(
     Compile / scalaSource := baseDirectory.value / "hw" / "spinal",
+    Test / scalaSource := baseDirectory.value / "tb" / "spinal",
     libraryDependencies ++= Seq(spinalCore, spinalLib, spinalIdslPlugin)
   )
 

build.sc

@@ -6,7 +6,8 @@ object projectname extends SbtModule {
   def scalaVersion = "2.12.16"
   override def millSourcePath = os.pwd
   def sources = T.sources(
-    millSourcePath / "hw" / "spinal"
+    millSourcePath / "hw" / "spinal",
+    millSourcePath / "tb" / "spinal"
   )
   def ivyDeps = Agg(
     ivy"com.github.spinalhdl::spinalhdl-core:$spinalVersion",