Fix a few more detritus issues [#719]

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.33.2-9005
+Version: 1.33.2-9006
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Imports:
     digest,

tests/Future-class.R

@@ -25,11 +25,11 @@ stopifnot(is.call(expr))
 
 clazzes <- list(
   sequential = SequentialFuture,
-  multisession = function(...) MultisessionFuture(..., workers = 2L),
+  multisession = function(...) MultisessionFuture(..., workers = I(1L)),
   sequential = SequentialFuture
 )
 if (supportsMulticore()) {
-  clazzes$multicore = function(...) MulticoreFuture(..., workers = 2L)
+  clazzes$multicore = function(...) MulticoreFuture(..., workers = I(1L))
 }
 
 for (clazz in clazzes) {
@@ -48,6 +48,9 @@ for (clazz in clazzes) {
   v <- value(f)
   print(v)
   stopifnot(v == 42L)
+
+  ## To avoid 'multisession' from leaving stray workers behind
+  ClusterRegistry(action = "stop")
 }
 
 message("*** Future class - exception ... DONE")

tests/globals,NSE.R

@@ -40,6 +40,10 @@ for (strategy in supportedStrategies()) {
   } %lazy% TRUE
   stopifnot(identical(v3, v0))
 
+  ## Make sure to shut down nested parallel workers
+  void %<-% { plan(sequential) }
+  print(void)
+
   message(sprintf("- Strategy: %s ... DONE", strategy))
 }