<filename>tests/test_main.py
import os
import sys
import unittest
from unittest.mock import patch
from click.testing import CliRunner

from mesa.main import cli


class TestCli(unittest.TestCase):
    """
    Test CLI commands
    """

    def setUp(self):
        self.old_sys_path = sys.path[:]
        self.runner = CliRunner()

    def tearDown(self):
        sys.path[:] = self.old_sys_path

    def test_run(self):
        with patch(
            "mesa.visualization.ModularVisualization.ModularServer"
        ) as ModularServer:
            example_dir = os.path.abspath(
                os.path.join(os.path.dirname(__file__), "../examples/wolf_sheep")
            )
            with self.runner.isolated_filesystem():
                result = self.runner.invoke(cli, ["runserver", example_dir])
                assert result.exit_code == 0, result.output
                assert ModularServer().launch.call_count == 1

<filename>tests/test_main.py
import os
import sys
import unittest
from unittest.mock import patch
from click.testing import CliRunner

from mesa.main import cli


class TestCli(unittest.TestCase):
    """
    Test CLI commands
    """

    def setUp(self):
        self.old_sys_path = sys.path[:]
        self.runner = CliRunner()

    def tearDown(self):
        sys.path[:] = self.old_sys_path

    def test_run(self):
        with patch(
            "mesa.visualization.ModularVisualization.ModularServer"
        ) as ModularServer:
            example_dir = os.path.abspath(
                os.path.join(os.path.dirname(__file__), "../examples/wolf_sheep")
            )
            with self.runner.isolated_filesystem():
                result = self.runner.invoke(cli, ["runserver", example_dir])
                assert result.exit_code == 0, result.output
                assert ModularServer().launch.call_count == 1

Test CLI commands