new_contents: # -*- coding: utf-8 -*-
  import pytest
  
  
  @pytest.mark.parametrize("cmd,expected_output", [
      ('install', "I'm install"),
      ('i', "I'm install"),
      ('uninstall', "I'm uninstall"),
      ('un', "I'm uninstall"),
      ('u', "Too many matches: uninstall, update"),
  ])
  def test_aliased_group(cmd, expected_output):
      import click
      from click.testing import CliRunner
      from pir.groups import AliasedGroup
  
      @click.group(cls=AliasedGroup)
      def pir():
          click.echo("I'm pir")
  
      @pir.command()
      def install():
          click.echo("I'm install")
  
      @pir.command()
      def uninstall():
          click.echo("I'm uninstall")
  
      @pir.command()
      def update():
          click.echo("I'm update")
  
      runner = CliRunner()
      result = runner.invoke(pir, [cmd])
      assert expected_output in result.output
  
subject: Add test for groups.py