make sure that when set to false parallel.do only uses 1 worker

src/utils/manageWorkersPool.m

@@ -20,7 +20,12 @@ function manageWorkersPool(action, opt)
   %    opt.parallelize.killOnExit = true;
   %
 
-  if ~isOctave() && opt.parallelize.do
+  if ~opt.parallelize.do
+    opt.parallelize.nbWorkers = 1;
+    opt.parallelize.killOnExit = true;
+  end
+
+  if ~isOctave()
 
     matlabVer = version('-release');
 
@@ -56,7 +61,11 @@ function manageWorkersPool(action, opt)
         if opt.parallelize.killOnExit
 
           if str2double(matlabVer(1:4)) > 2013
-            delete(gcp);
+
+            pool = gcp('nocreate');
+            if ~isempty(pool)
+              delete(gcp);
+            end
 
           else
             matlabpool close;

tests/test_manageWorkersPool.m

@@ -0,0 +1,69 @@
+function test_suite = test_manageWorkersPool %#ok<*STOUT>
+  try % assignment of 'localfunctions' is necessary in Matlab >= 2016
+    test_functions = localfunctions(); %#ok<*NASGU>
+  catch % no problem; early Matlab versions can use initTestSuite fine
+  end
+  initTestSuite;
+end
+
+function test_manageWorkersPoolBasic()
+
+  opt.parallelize.do = true;
+  opt.parallelize.nbWorkers = 3;
+  opt.parallelize.killOnExit = true;
+
+  matlabVer = version('-release');
+
+  manageWorkersPool('close', opt);
+
+  manageWorkersPool('open', opt);
+
+  if ~isOctave()
+    if str2double(matlabVer(1:4)) > 2013
+
+      pool = gcp('nocreate');
+      nbWorkers = pool.NumWorkers;
+
+    else
+      nbWorkers = matlabpool('size'); %#ok<DPOOL>
+
+    end
+
+    manageWorkersPool('close', opt);
+
+    assertEqual(nbWorkers, opt.parallelize.nbWorkers);
+
+  end
+
+end
+
+function test_manageWorkersPoolNoParallel()
+
+  opt.parallelize.do = false;
+  opt.parallelize.nbWorkers = 3;
+  opt.parallelize.killOnExit = true;
+
+  matlabVer = version('-release');
+
+  manageWorkersPool('close', opt);
+
+  manageWorkersPool('open', opt);
+
+  if ~isOctave()
+    if str2double(matlabVer(1:4)) > 2013
+
+      pool = gcp('nocreate');
+      nbWorkers = pool.NumWorkers;
+
+    else
+      nbWorkers = matlabpool('size'); %#ok<DPOOL>
+
+    end
+
+    manageWorkersPool('close', opt);
+
+    assertEqual(nbWorkers, 1);
+
+  end
+
+end