anchor.diff:  
   let
     addGitRev = subject: subject.overrideAttrs (drv: { GITREV = gitrev; });
  +  addRealTimeTestLogs = drv: overrideCabal drv (attrs: {
  +    testTarget = "--log=test.log || (sleep 10 && kill $TAILPID && false)";
  +    preCheck = ''
  +      mkdir -p dist/test
  +      touch dist/test/test.log
  +      tail -F dist/test/test.log &
  +      export TAILPID=$!
  +    '';
  +    postCheck = ''
  +      sleep 10
  +      kill $TAILPID
  +    '';
  +  });
     cardanoPkgs = ((import ./pkgs { inherit pkgs; }).override {
       overrides = self: super: {
         cardano-sl-core = overrideCabal super.cardano-sl-core (drv: {
  
positive.code:         configureFlags = (drv.configureFlags or []) ++ [
            "-f-asserts"
          ];
          testTarget = "--log=test.log || (sleep 10 && kill $TAILPID && false)";
          preCheck = ''
            mkdir -p dist/test
            touch dist/test/test.log
            tail -F dist/test/test.log &
            export TAILPID=$!
          '';
          postCheck = ''
            sleep 10
            kill $TAILPID
          '';
          # waiting on load-command size fix in dyld
          doCheck = ! pkgs.stdenv.isDarwin;
          passthru = {
  
negative.code:         };
        });
  
        cardano-sl-client = addRealTimeTestLogs super.cardano-sl-client;
        cardano-sl-auxx = addGitRev super.cardano-sl-auxx;
        cardano-sl-node = addGitRev super.cardano-sl-node;
        cardano-sl-wallet = addGitRev (justStaticExecutables super.cardano-sl-wallet);
  