anchor.diff:      subtest "single node", sub {
         $simple->start();
         $simple->waitForUnit("etcd.service");
  -      $simple->succeed("etcdctl set /foo/bar 'Hello world'");
  +      $simple->waitUntilSucceeds("etcdctl set /foo/bar 'Hello world'");
         $simple->waitUntilSucceeds("etcdctl get /foo/bar | grep 'Hello world'");
       };
   
  
positive.code:       $discovery2->start();
        $discovery1->waitForUnit("etcd.service");
        $discovery2->waitForUnit("etcd.service");
        $discovery1->succeed("etcdctl set /foo/bar 'Hello world'");
        $discovery2->waitUntilSucceeds("etcdctl get /foo/bar | grep 'Hello world'");
      };
    '';
  
negative.code:       $node2->start();
        $node1->waitForUnit("etcd.service");
        $node2->waitForUnit("etcd.service");
        $node1->waitUntilSucceeds("etcdctl set /foo/bar 'Hello world'");
        $node2->waitUntilSucceeds("etcdctl get /foo/bar | grep 'Hello world'");
        $node1->shutdown();
        $node2->shutdown();
  