withPostgreSQL.nix

withPostgreSQL = drv: pkgs.haskell.lib.overrideCabal drv (a: {
    testToolDepends = (a.testToolDepends or []) ++
      [ pkgs.ephemeralpg pkgs.postgresql pkgs.getopt ];
    preCheck = (a.preCheck or "") + ''
      export TEST_PG_CONN_STRING=$(pg_tmp -w 600)
    '';
    # we need the temporary directory from pg_tmp
    # so extract it out of $TEST_PG_CONN_STRING
    postCheck = (a.postCheck or "") + ''
      pg_tmp stop -d $(echo ''${TEST_PG_CONN_STRING#*=} | sed 's:%2F:/:g')
    '';
  });