[Django]-How can I call a custom Django manage.py command directly from a test driver?

Rather than do the call_command trick, you can run your task by doing:

from myapp.management.commands import my_management_task
cmd = my_management_task.Command()
opts = {} # kwargs for your command -- lets you override stuff for testing...
cmd.handle_noargs(**opts)

the following code:

from django.core.management import call_command
call_command('collectstatic', verbosity=3, interactive=False)
call_command('migrate', 'myapp', verbosity=3, interactive=False)

…is equal to the following commands typed in terminal:

$ ./manage.py collectstatic --noinput -v 3
$ ./manage.py migrate myapp --noinput -v 3

See running management commands from django docs.

The Django documentation on the call_command fails to mention that out must be redirected to sys.stdout. The example code should read:

from django.core.management import call_command
from django.test import TestCase
from django.utils.six import StringIO
import sys

class ClosepollTest(TestCase):
    def test_command_output(self):
        out = StringIO()
        sys.stdout = out
        call_command('closepoll', stdout=out)
        self.assertIn('Expected output', out.getvalue())

Building on Nate’s answer I have this:

def make_test_wrapper_for(command_module):
    def _run_cmd_with(*args):
        """Run the possibly_add_alert command with the supplied arguments"""
        cmd = command_module.Command()
        (opts, args) = OptionParser(option_list=cmd.option_list).parse_args(list(args))
        cmd.handle(*args, **vars(opts))
    return _run_cmd_with

Usage:

from myapp.management import mycommand
cmd_runner = make_test_wrapper_for(mycommand)
cmd_runner("foo", "bar")

The advantage here being that if you’ve used additional options and OptParse, this will sort the out for you. It isn’t quite perfect – and it doesn’t pipe outputs yet – but it will use the test database. You can then test for database effects.

I am sure use of Micheal Foords mock module and also rewiring stdout for the duration of a test would mean you could get some more out of this technique too – test the output, exit conditions etc.

The advanced way to run manage command with a flexible arguments and captured output

argv = self.build_argv(short_dict=kwargs)
cmd = self.run_manage_command_raw(YourManageCommandClass, argv=argv)
# Output is saved cmd.stdout.getvalue() / cmd.stderr.getvalue()

Add code to your base Test class

    @classmethod
    def build_argv(cls, *positional, short_names=None, long_names=None, short_dict=None, **long_dict):
        """
        Build argv list which can be provided for manage command "run_from_argv"
        1) positional will be passed first as is
        2) short_names with be passed after with one dash (-) prefix
        3) long_names with be passed after with one tow dashes (--) prefix
        4) short_dict with be passed after with one dash (-) prefix key and next item as value
        5) long_dict with be passed after with two dashes (--) prefix key and next item as value
        """
        argv = [__file__, None] + list(positional)[:]

        for name in short_names or []:
            argv.append(f'-{name}')

        for name in long_names or []:
            argv.append(f'--{name}')

        for name, value in (short_dict or {}).items():
            argv.append(f'-{name}')
            argv.append(str(value))

        for name, value in long_dict.items():
            argv.append(f'--{name}')
            argv.append(str(value))

        return argv

    @classmethod
    def run_manage_command_raw(cls, cmd_class, argv):
        """run any manage.py command as python object"""
        command = cmd_class(stdout=io.StringIO(), stderr=io.StringIO())
        
        with mock.patch('django.core.management.base.connections.close_all'):  
            # patch to prevent closing db connecction
            command.run_from_argv(argv)
        return command