Tweak TestGroup

Author: som-snytt

compiler/test/dotty/tools/dotc/BootstrappedOnlyCompilationTests.scala

@@ -4,9 +4,7 @@ package dotc
 
 import scala.language.unsafeNulls
 
-import org.junit.{ Test, BeforeClass, AfterClass }
-import org.junit.Assert._
-import org.junit.Assume._
+import org.junit.{ Test, AfterClass }
 import org.junit.experimental.categories.Category
 
 import scala.concurrent.duration._
@@ -96,7 +94,7 @@ class BootstrappedOnlyCompilationTests {
   // Negative tests ------------------------------------------------------------
 
   @Test def negMacros: Unit = {
-    implicit val testGroup: TestGroup = TestGroup("compileNegWithCompiler")
+    given TestGroup = TestGroup("negMacros")
     compileFilesInDir("tests/neg-macros", defaultOptions.and("-Xcheck-macros"))
       .checkExpectedErrors()
   }

compiler/test/dotty/tools/vulpix/ParallelTesting.scala

@@ -4,35 +4,27 @@ package vulpix
 
 import scala.language.unsafeNulls
 
-import java.io.{File => JFile, IOException, PrintStream, ByteArrayOutputStream}
-import java.lang.System.{lineSeparator => EOL}
-import java.net.URL
+import java.io.File => JFile
 import java.nio.file.StandardCopyOption.REPLACE_EXISTING
-import java.nio.file.{Files, NoSuchFileException, Path, Paths}
+import java.nio.file.{Files, NoSuchFileException, Paths}
 import java.nio.charset.{Charset, StandardCharsets}
-import java.text.SimpleDateFormat
 import java.util.{HashMap, Timer, TimerTask}
 import java.util.concurrent.{ExecutionException, TimeUnit, TimeoutException, Executors => JExecutors}
 
 import scala.collection.mutable
 import scala.io.{Codec, Source}
 import scala.jdk.CollectionConverters.*
 import scala.util.{Random, Try, Failure => TryFailure, Success => TrySuccess, Using}
-import scala.util.control.NonFatal
-import scala.util.matching.Regex
 import scala.collection.mutable.ListBuffer
 
 import dotc.{Compiler, Driver}
 import dotc.core.Contexts.*
-import dotc.decompiler
 import dotc.report
 import dotc.interfaces.Diagnostic.ERROR
 import dotc.reporting.{Reporter, TestReporter}
 import dotc.reporting.Diagnostic
-import dotc.config.Config
-import dotc.util.{DiffUtil, SourceFile, SourcePosition, Spans, NoSourcePosition}
+import dotc.util.{SourceFile, SourcePosition, Spans, NoSourcePosition}
 import io.AbstractFile
-import dotty.tools.vulpix.TestConfiguration.defaultOptions
 
 /** A parallel testing suite whose goal is to integrate nicely with JUnit
  *
@@ -1452,7 +1444,7 @@ trait ParallelTesting extends RunnerOrchestration { self =>
    *  By default, files are compiled in alphabetical order. An optional seed
    *  can be used for randomization.
    */
-  def compileDir(f: String, flags: TestFlags, randomOrder: Option[Int] = None, recursive: Boolean = true)(implicit testGroup: TestGroup): CompilationTest = {
+  def compileDir(f: String, flags: TestFlags, randomOrder: Option[Int] = None, recursive: Boolean = true)(using testGroup: TestGroup): CompilationTest = {
     val outDir = defaultOutputDir + testGroup + JFile.separator
     val sourceDir = new JFile(f)
     checkRequirements(f, sourceDir, outDir)

compiler/test/dotty/tools/vulpix/TestGroup.scala

@@ -2,14 +2,15 @@ package dotty.tools.vulpix
 
 /** Test groups are used to ensure that the output of tests do not overlap.
  *
- *  It can be used to disambiguate ouputs of tests that test the same file but with different options as shown in the following example.
+ *  A test group can be used to disambiguate outputs of tests that test the same file
+ *  but with different options as shown in the following example.
+ *
  *    compileFilesInDir("tests/pos", defaultOptions)(TestGroup("compileStdLib")) // will output in ./out/compileStdLib/...
  *    compileFilesInDir("tests/pos", defaultOptimised)(TestGroup("optimised/testOptimised")) // will output in ./out/optimised/testOptimised/...
  */
-class TestGroup(val name: String) extends AnyVal {
-  override def toString: String = name
-}
 
-object TestGroup {
-  def apply(name: String): TestGroup = new TestGroup(name)
-}
+opaque type TestGroup = String
+
+object TestGroup:
+  inline def apply(inline name: String): TestGroup = name
+  extension (inline group: TestGroup) inline def name: String = group