External Test Plugin¶
Overview¶
The External Test Plugin supports testing of a cmd2 application by exposing access cmd2
commands with the same context as from within a cmd2 Python Scripts. This interface
captures stdout
, stderr
, as well as any application-specific data returned by the command. This also allows
for verification of an application’s support for Python Scripts and enables the cmd2
application to be tested as part of a larger system integration test.
Example cmd2 Application¶
The following short example shows how to mix in the external test plugin to create a fixture for testing your cmd2 application.
Define your cmd2 application
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')
Defining the test fixture¶
In your test, define a fixture for your cmd2 application
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()
Writing Tests¶
Now write your tests that validate your application using the app_cmd()
function to access the cmd2 application’s commands. This allows invocation of the application’s commands in the
same format as a user would type. The results from calling a command matches what is returned
from running an python script with cmd2’s run_pyscript command, which provides
stdout
, stderr
, and the command’s result data.
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