shared_examples_for "a command that does not block" do |opts = {}|
  if opts[:supports_stderr]
    it "does not block if the command output a lot on stderr" do
      Timeout.timeout(5) do
        output = subject.call("ruby -e '$stdout.puts %{hello}; $stderr.puts %{goodbye}*10_000'")

      expect(output.output).to eq "hello\n"
      expect(output.error_output).to eq "#{"goodbye" * 10_000}\n"
      end
    end
  end

  it 'does not block if the command outputs a lot of data' do
    garbage_file = Tempfile.new("garbage")
    10.times{ garbage_file.write("A" * 1024 * 1024) }

    Timeout.timeout(5) do
      output = subject.call("cat '#{garbage_file.path}'")
      expect($?.exitstatus).to eq(0)
      expect(output.output.length).to eq(10 * 1024 * 1024)
    end

    garbage_file.close
  end
end