bundlerEnv ruby2.7 test case

Gemfile

# frozen_string_literal: true

source "https://rubygems.org"

gem "thor"

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    thor (1.0.1)

PLATFORMS
  ruby

DEPENDENCIES
  thor

BUNDLED WITH
   1.17.2

gemset.nix

{
  thor = {
    groups = ["default"];
    platforms = [];
    source = {
      remotes = ["https://rubygems.org"];
      sha256 = "1xbhkmyhlxwzshaqa7swy2bx6vd64mm0wrr8g3jywvxy7hg0cwkm";
      type = "gem";
    };
    version = "1.0.1";
  };
}

test.nix

{ rubyAttr ? "ruby_2_7" }:
let
  pkgs = import <nixpkgs> {};

  bundlerEnv = pkgs.bundlerEnv.override {
    bundler = pkgs.bundler.override {
      ruby = pkgs."${rubyAttr}";
    };
  };
in

bundlerEnv {
  pname = "thor";

  ruby = pkgs."${rubyAttr}";

  gemdir = ./.;
}