Use exec in tests to get it tested

Author: Slamdunk

tests/cli/StopOnFailureCest.php

@@ -17,8 +17,8 @@ public function parallelProcessesGetStoppedIfStopOnFailIsSet(CliGuy $I)
         /** @var \Robo\Task\Base\ParallelExec $parallel */
         $parallel = $I->taskParallelExec();
         $parallel->stopOnFail(true);
-        $parallel->process($I->taskExec(sprintf('touch %s && false', escapeshellarg($filenameOk))));
-        $parallel->process($I->taskExec(sprintf('sleep 3 && touch %s', escapeshellarg($filenameKo))));
+        $parallel->process($I->taskExec(sprintf('exec touch %s && false', escapeshellarg($filenameOk))));
+        $parallel->process($I->taskExec(sprintf('exec sleep 3 && touch %s', escapeshellarg($filenameKo))));
         $parallel->run();
 
         $I->seeFileFound($filenameOk);