import cmd2
class ExampleApp(cmd2.Cmd):
    """An class to show how to use a plugin"""
    def __init__(self, *args, **kwargs):
        # gotta have this or neither the plugin or cmd2 will initialize
        super().__init__(*args, **kwargs)
    def do_something(self, arg):
        self.last_result = 5
        self.poutput('this is the something command')

import cmd2_ext_test
import pytest
class ExampleAppTester(cmd2_ext_test.ExternalTestMixin, ExampleApp):
    def __init__(self, *args, **kwargs):
        # gotta have this or neither the plugin or cmd2 will initialize
        super().__init__(*args, **kwargs)
@pytest.fixture
def example_app():
    app = ExampleAppTester()
    app.fixture_setup()
    yield app
    app.fixture_teardown()

from cmd2 import CommandResult
def test_something(example_app):
    # execute a command
    out = example_app.app_cmd("something")
    # validate the command output and result data
    assert isinstance(out, CommandResult)
    assert str(out.stdout).strip() == 'this is the something command'
    assert out.data == 5