anchor.diff:  
     # Tests fail in Darwin sandbox.
     doCheck = !stdenv.isDarwin;
  +
  +  postInstall = ''
  +    installShellCompletion --cmd ocm \
  +      --bash <($out/bin/ocm completion bash) \
  +      --fish <($out/bin/ocm completion fish) \
  +      --zsh <($out/bin/ocm completion zsh)
  +  '';
   
     passthru.tests.version = testers.testVersion {
       package = ocm;
  
positive.code: { lib, buildGoModule, fetchFromGitHub, stdenv, testers, ocm }:
  
  buildGoModule rec {
    pname = "ocm";
    version = "0.1.63";
  
    src = fetchFromGitHub {
      owner = "openshift-online";
      repo = "ocm-cli";
      rev = "v${version}";
      sha256 = "sha256-wBKW2WS1+JmWOFCArmrlVfUTEqFYF7aq1OBrUo7e4ac=";
    };
  
    vendorSha256 = "sha256-LyQ/F+E0y1gQtpGSyPEB2z2ImorA7mjY3QjrRORakIo=";
  
    # Strip the final binary.
    ldflags = [ "-s" "-w" ];
  
    # Tests expect the binary to be located in the root directory.
    preCheck = ''
  
negative.code:     license = licenses.asl20;
      homepage = "https://github.com/openshift-online/ocm-cli";
      maintainers = with maintainers; [ stehessel ];
      platforms = platforms.all;
    };
  }
  