Test with Ruby 3

- Add `.ruby-version` file (which is also used by `ruby/setup-ruby`)
- Add `.rubocop.yml` symlink so that `brew style` and `rubocop` (e.g.
  run by VSCode) are consistent
- Don't `bundle install` with an ancient Bundler
- Fix `bundle_utils_spec` without changing behaviour

.github/workflows/tests.yml

@@ -35,7 +35,6 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: '2.6'
         bundler-cache: true
 
     - name: Run RSpec tests

.rubocop.yml

@@ -0,0 +1 @@
+../../../.rubocop.yml

.ruby-version

@@ -0,0 +1 @@
+3.1.4

Gemfile.lock

@@ -48,6 +48,3 @@ DEPENDENCIES
   rspec
   simplecov
   simplecov-cobertura
-
-BUNDLED WITH
-   1.17.3

spec/bundle_utils_spec.rb

@@ -14,16 +14,18 @@
   end
 
   context "when the system call fails" do
-    before do
-      allow_any_instance_of(Process::Status).to receive(:success?).and_return(false)
-    end
-
     it "emits all stdout output even if verbose is false" do
-      expect { described_class.system "echo", "foo", verbose: false }.to output("foo\n").to_stdout_from_any_process
+      expect do
+        described_class.system "/bin/bash", "-c", "echo foo && false",
+                               verbose: false
+      end.to output("foo\n").to_stdout_from_any_process
     end
 
     it "emits all stdout output only once if verbose is true" do
-      expect { described_class.system "echo", "foo", verbose: true }.to output("foo\n").to_stdout_from_any_process
+      expect do
+        described_class.system "/bin/bash", "-c", "echo foo && true",
+                               verbose: true
+      end.to output("foo\n").to_stdout_from_any_process
     end
   end
 

spec/spec_helper.rb

@@ -70,7 +70,7 @@ def linux?
   RSpec::Support::ObjectFormatter.default_instance.max_formatted_output_length = nil
 
   config.around do |example|
-    Bundler.with_clean_env { example.run }
+    Bundler.with_original_env { example.run }
   end
 
   config.before(:each, :needs_linux) do