testing click python applications

Question

click is a python package for creating nice commandline interfaces for your applications. I have been playing with click a bit and today pushed this simple roman numeral converter on github.

What I want to do now is to test my click application. I am reading through the documentation, but don't know how to run the tests.

Does anyone have experience with testing click applications?

Circumvent

So put tests inside toroman.py and run it? I have tried but it does not work. – Circumvent

From the Testing chapter in the docs, it looks like you can write tests as separate scripts that use click.testing.CliRunner, and then you run the tests just by running those scripts the same as any other Python script. What part of that is confusing? Where are you stuck? – Raddi

Yes, but when I run the python file that contains the tests I don't get any output to tell me if they passed or failed. – Circumvent

OK, then show us a simple example of a click app and CliRunner tests, and how you're running them, don't make us guess at what you did and what parts you may or may not understsand. – Raddi

Answer 1

Putting the code below in test_greet.py:

import click
from click.testing import CliRunner

def test_greet():
    @click.command()
    @click.argument('name')
    def greet(name):
        click.echo('Hello %s' % name)

    runner = CliRunner()
    result = runner.invoke(greet, ['Sam'])
    assert result.output == 'Hello Sam\n'

if __name__ == '__main__':
    test_greet()

If simply called with python test_greet.py the tests pass and nothing is shown. When used in a testing framework, it performs as expected. For example nosetests test_greet.py returns

.
----------------------------------------------------------------------
Ran 1 test in 0.002s

OK

Circumvent

This example function works as expected if embedded in testing framework like nose or pytest see example in click – Emporium

This is just an example of a tiny in-line function how do I test a script that uses click?? – Dove

Answer 2

pytest has the handlers for the asserts.

To run tests against an existing script, it must be 'imported'.

import click
from click.testing import CliRunner
from click_app import configure, cli

def test_command_configure():
    runner = CliRunner()
    result = runner.invoke(cli, ["configure"])
    assert result.exit_code == 0
    assert result.output == 'configure'

Docia

Would you consider adding source for 'click_app.py' to complete the example? – Linnealinnean