anchor.diff:        $cass0->waitUntilSucceeds("nc -z localhost 7199");
         $cass0->waitUntilSucceeds("nodetool describecluster | grep 'Name: ${clusterName}'");
       };
  +    subtest "Heap limit set correctly", sub {
  +      # Nodetool takes a while until it can display info
  +      $cass0->waitUntilSucceeds('nodetool info');
  +      $cass0->succeed('${checkHeapLimitCommand}');
  +    };
   
       # Check cluster interaction
       subtest "Bring up cluster", sub {
  
positive.code:       rpcAddress = ipAddress;
        seedAddresses = [ "192.168.1.1" ];
        package = testPackage;
      };
    nodeCfg = ipAddress: extra: {pkgs, config, ...}:
      { environment.systemPackages = [ testPackage ];
  
negative.code:   # Change this to test a different version of Cassandra:
    testPackage = pkgs.cassandra;
    clusterName = "NixOS Automated-Test Cluster";
  
    numMaxHeapSize = "400";
    getHeapLimitCommand = ''
      nodetool info | grep "^Heap Memory" | awk \'{print $NF}\'
    '';
    checkHeapLimitCommand = ''
      [ 1 -eq "$(echo "$(${getHeapLimitCommand}) < ${numMaxHeapSize}" | ${pkgs.bc}/bin/bc)" ]
    '';
  
    cassandraCfg = ipAddress:
      { enable = true;
  