Merge pull request #8193 from eed3si9n/wip/fork-parallel

[2.x] Flip testForkedParallel to true

main/src/main/scala/sbt/Defaults.scala

@@ -201,7 +201,7 @@ object Defaults extends BuildCommon {
       discoveredJavaHomes := CrossJava.discoverJavaHomes,
       javaHomes :== ListMap.empty,
       fullJavaHomes := CrossJava.expandJavaHomes(discoveredJavaHomes.value ++ javaHomes.value),
-      testForkedParallel :== false,
+      testForkedParallel :== true,
       javaOptions :== Nil,
       sbtPlugin :== false,
       isMetaBuild :== false,

sbt-app/src/sbt-test/tests/fork-parallel/build.sbt

@@ -1,27 +1,23 @@
 import Tests._
 import Defaults._
 
-ThisBuild / scalaVersion := "2.12.20"
+scalaVersion := "2.12.20"
 val check = taskKey[Unit]("Check that tests are executed in parallel")
 
-lazy val root = (project in file("."))
-  .settings(
-    libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % Test,
-    Test / fork := true,
+libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % Test
+Test / fork := true
+
 check := {
   val nbProc = java.lang.Runtime.getRuntime().availableProcessors()
   val log = streams.value.log
-      if( nbProc < 4 ) {
+  if nbProc < 4 then
     log.warn("With fewer than 4 processors this test is meaningless")
     // mimic behavior expected by scripted
-        if (!testForkedParallel.value) sys.error("Exiting with error (note: test not performed)")
-      } else {
+    if !testForkedParallel.value then sys.error("Exiting with error (note: test not performed)")
+  else
     // we've got at least 4 processors, we'll check the upper end but also 3 and 4 as the upper might not
     // be reached if the system is under heavy load.
-        if( ! (file("max-concurrent-tests_3").exists() || file("max-concurrent-tests_4").exists() ||
-               file("max-concurrent-tests_" + (nbProc -1)).exists() || file("max-concurrent-tests_" + nbProc).exists())) {
+    if ! (file("max-concurrent-tests_3").exists() || file("max-concurrent-tests_4").exists() ||
+           file("max-concurrent-tests_" + (nbProc -1)).exists() || file("max-concurrent-tests_" + nbProc).exists()) then
       sys.error("Forked tests were not executed in parallel!")
 }
-      }
-    }
-  )

sbt-app/src/sbt-test/tests/fork-parallel/test

@@ -1,8 +1,13 @@
 # Note: this test is meaningless on less than four cores
 
-> testFull
--> check
-> clean
-> set testForkedParallel := true
 > testFull
 > check
+> clean
+$ delete max-concurrent-tests_1
+$ delete max-concurrent-tests_2
+$ delete max-concurrent-tests_3
+$ delete max-concurrent-tests_4
+
+> set testForkedParallel := false
+> testFull
+-> check