core/pkgs/build-support/fetchurl/tests.nix

{
  testers,
  fetchurl,
  jq,
  moreutils,
  ...
}:
{
  # Tests that we can send custom headers with spaces in them
  header =
    let
      headerValue = "Test '\" <- These are some quotes";
    in
    testers.invalidateFetcherByDrvHash fetchurl {
      url = "https://httpbin.org/headers";
      sha256 = builtins.hashString "sha256" (headerValue + "\n");
      curlOptsList = [
        "-H"
        "Hello: ${headerValue}"
      ];
      postFetch = ''
        ${jq}/bin/jq -r '.headers.Hello' $out | ${moreutils}/bin/sponge $out
      '';
    };
}