Merge branch 'feature-3.1-cache-thread-pool' of https://github.com/cheeseng/scalatest into cheeseng-feature-3.1-cache-thread-pool

Author: bvenners

scalatest-test/src/test/scala/org/scalatest/tools/FrameworkSuite.scala

@@ -1096,7 +1096,7 @@ class FrameworkSuite extends FunSuite {
     assert(iae.getMessage === "-P without specifying <numthreads> is not supported when running ScalaTest from sbt, please use sbt parallel configuration instead.")
   }
 
-  test("Framework.runner accept without problem when -P 4 is passed in") {
+  test("Framework.runner accept without problem when -P4 is passed in") {
     framework.runner(Array("-P4"), Array.empty, testClassLoader)
   }
 

scalatest/src/main/scala/org/scalatest/tools/Framework.scala

@@ -698,7 +698,11 @@ class Framework extends SbtFramework {
       else
         concurrentConfig.numThreads
 
-    val execSvc: ExecutorService = Executors.newFixedThreadPool(poolSize, threadFactory)
+    val execSvc: ExecutorService =
+      if (poolSize > 0)
+        Executors.newFixedThreadPool(poolSize, threadFactory)
+      else
+        Executors.newCachedThreadPool(threadFactory)
 
     private def createTask(td: TaskDef): ScalaTestTask = 
       new ScalaTestTask(

scalatest/src/main/scala/org/scalatest/tools/Runner.scala

@@ -1248,8 +1248,10 @@ object Runner {
             // Because some tests may do IO, will create a pool of 2 times the number of processors reported
             // by the Runtime's availableProcessors method.
             val poolSize =
-              if (concurrentConfig.numThreads > 0) concurrentConfig.numThreads
-              else Runtime.getRuntime.availableProcessors * 2
+            if (concurrentConfig.numThreads == 0)
+              Runtime.getRuntime.availableProcessors * 2
+            else
+              concurrentConfig.numThreads
 
             val distributedSuiteSorter = 
               if (concurrentConfig.enableSuiteSortingReporter)
@@ -1272,7 +1274,11 @@ object Runner {
                   thread
                 }
               }
-            val execSvc: ExecutorService = Executors.newFixedThreadPool(poolSize, threadFactory)
+            val execSvc: ExecutorService =
+              if (poolSize > 0)
+                Executors.newFixedThreadPool(poolSize, threadFactory)
+              else
+                Executors.newCachedThreadPool(threadFactory)
             try {
 
               val distributor = new ConcurrentDistributor(Args(dispatch, stopper, Filter(if (tagsToIncludeSet.isEmpty) None else Some(tagsToIncludeSet), tagsToExcludeSet), configMap, None, tracker, chosenStyleSet, false, None, None), execSvc)