chore: add support for sbt-test in the new build

.github/workflows/stdlib.yaml

@@ -333,3 +333,26 @@ jobs:
       - uses: sbt/setup-sbt@v1
       - name: Test `tasty-core-bootstrapped`
         run: ./project/scripts/sbt tasty-core-bootstrapped-new/test
+
+  sbt-test:
+    runs-on: ubuntu-latest
+    ##needs: [scala3-sbt-bridge-bootstrapped,
+    ##        scala3-library-bootstrapped,
+    ##        scala3-compiler-bootstrapped,
+    ##        tasty-core-bootstrapped,
+    ##        scala3-library-sjs,
+    ##        scala3-tasty-inspector,
+    ##        scala3-staging] Add when we add support for caching here
+    steps:
+      - name: Git Checkout
+        uses: actions/checkout@v5
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 17
+          cache: 'sbt'
+      - uses: sbt/setup-sbt@v1
+      - name: Run `sbt-test`
+        run: ./project/scripts/sbt sbt-test-new/scripted

build.sbt

@@ -59,6 +59,7 @@ val sjsJUnitTests = Build.sjsJUnitTests
 val sjsCompilerTests = Build.sjsCompilerTests
 
 val `sbt-test` = Build.`sbt-test`
+val `sbt-test-new` = Build.`sbt-test-new`
 
 inThisBuild(Build.thisBuildSettings)
 inScope(Global)(Build.globalSettings)

project/Build.scala

@@ -2368,6 +2368,27 @@ object Build {
       }.taskValue,
     )
 
+  // ==============================================================================================
+  // ========================================= TEST SUITE =========================================
+  // ==============================================================================================
+
+  lazy val `sbt-test-new` = project.in(file("sbt-test"))
+    .enablePlugins(ScriptedPlugin)
+    .settings(
+      sbtTestDirectory := baseDirectory.value,
+      // The batch mode accidentally became the default with no way to disable
+      // it in sbt 1.4 (https://github.com/sbt/sbt/issues/5913#issuecomment-716003195).
+      // We enable it explicitly here to make it clear that we're using it.
+      scriptedBatchExecution := true,
+      scriptedLaunchOpts ++= Seq(
+        s"-Dplugin.scalaVersion=${dottyVersion}",
+        s"-Dplugin.scala2Version=${stdlibVersion(Bootstrapped)}",
+        s"-Dplugin.scalaJSVersion=${scalaJSVersion}",
+      ),
+      scriptedBufferLog := true,
+      scripted := scripted.dependsOn(`scala3-bootstrapped-new` / publishLocalBin).evaluated
+    )
+
   def dottyLibrary(implicit mode: Mode): Project = mode match {
     case NonBootstrapped => `scala3-library`
     case Bootstrapped => `scala3-library-bootstrapped`