flake8/tests/unit/test_plugin.py

"""Tests for flake8.plugins.manager.Plugin."""
import argparse

import mock
import pytest

from flake8 import exceptions
from flake8.options import manager as options_manager
from flake8.plugins import manager


def test_load_plugin_fallsback_on_old_setuptools():
    """Verify we fallback gracefully to on old versions of setuptools."""
    entry_point = mock.Mock(spec=['load'])
    plugin = manager.Plugin('T000', entry_point)

    plugin.load_plugin()
    entry_point.load.assert_called_once_with()


def test_load_plugin_is_idempotent():
    """Verify we use the preferred methods on new versions of setuptools."""
    entry_point = mock.Mock(spec=['load'])
    plugin = manager.Plugin('T000', entry_point)

    plugin.load_plugin()
    plugin.load_plugin()
    plugin.load_plugin()
    entry_point.load.assert_called_once_with()


def test_load_plugin_catches_and_reraises_exceptions():
    """Verify we raise our own FailedToLoadPlugin."""
    entry_point = mock.Mock(spec=['load'])
    entry_point.load.side_effect = ValueError('Test failure')
    plugin = manager.Plugin('T000', entry_point)

    with pytest.raises(exceptions.FailedToLoadPlugin):
        plugin.load_plugin()


def test_load_noncallable_plugin():
    """Verify that we do not load a non-callable plugin."""
    entry_point = mock.Mock(spec=['load'])
    entry_point.load.return_value = mock.NonCallableMock()
    plugin = manager.Plugin('T000', entry_point)

    with pytest.raises(exceptions.FailedToLoadPlugin):
        plugin.load_plugin()
    entry_point.load.assert_called_once_with()


def test_plugin_property_loads_plugin_on_first_use():
    """Verify that we load our plugin when we first try to use it."""
    entry_point = mock.Mock(spec=['load'])
    plugin = manager.Plugin('T000', entry_point)

    assert plugin.plugin is not None
    entry_point.load.assert_called_once_with()


def test_execute_calls_plugin_with_passed_arguments():
    """Verify that we pass arguments directly to the plugin."""
    entry_point = mock.Mock(spec=['load'])
    plugin_obj = mock.Mock()
    plugin = manager.Plugin('T000', entry_point)
    plugin._plugin = plugin_obj

    plugin.execute('arg1', 'arg2', kwarg1='value1', kwarg2='value2')
    plugin_obj.assert_called_once_with(
        'arg1', 'arg2', kwarg1='value1', kwarg2='value2'
    )

    # Extra assertions
    assert entry_point.load.called is False


def test_version_proxies_to_the_plugin():
    """Verify that we pass arguments directly to the plugin."""
    entry_point = mock.Mock(spec=['load'])
    plugin_obj = mock.Mock(spec_set=['version'])
    plugin_obj.version = 'a.b.c'
    plugin = manager.Plugin('T000', entry_point)
    plugin._plugin = plugin_obj

    assert plugin.version == 'a.b.c'


def test_register_options():
    """Verify we call add_options on the plugin only if it exists."""
    # Set up our mocks and Plugin object
    entry_point = mock.Mock(spec=['load'])
    plugin_obj = mock.Mock(spec_set=['name', 'version', 'add_options',
                                     'parse_options'])
    option_manager = mock.MagicMock(spec=options_manager.OptionManager)
    plugin = manager.Plugin('T000', entry_point)
    plugin._plugin = plugin_obj

    # Call the method we're testing.
    plugin.register_options(option_manager)

    # Assert that we call add_options
    plugin_obj.add_options.assert_called_once_with(option_manager)


def test_register_options_checks_plugin_for_method():
    """Verify we call add_options on the plugin only if it exists."""
    # Set up our mocks and Plugin object
    entry_point = mock.Mock(spec=['load'])
    plugin_obj = mock.Mock(spec_set=['name', 'version', 'parse_options'])
    option_manager = mock.Mock(spec=['register_plugin'])
    plugin = manager.Plugin('T000', entry_point)
    plugin._plugin = plugin_obj

    # Call the method we're testing.
    plugin.register_options(option_manager)

    # Assert that we register the plugin
    assert option_manager.register_plugin.called is False


def test_provide_options():
    """Verify we call add_options on the plugin only if it exists."""
    # Set up our mocks and Plugin object
    entry_point = mock.Mock(spec=['load'])
    plugin_obj = mock.Mock(spec_set=['name', 'version', 'add_options',
                                     'parse_options'])
    option_values = argparse.Namespace(enable_extensions=[])
    option_manager = mock.Mock()
    plugin = manager.Plugin('T000', entry_point)
    plugin._plugin = plugin_obj

    # Call the method we're testing.
    plugin.provide_options(option_manager, option_values, None)

    # Assert that we call add_options
    plugin_obj.parse_options.assert_called_once_with(
        option_manager, option_values, None
    )


@pytest.mark.parametrize('ignore_list, code, expected_list', [
    (['E', 'W', 'F', 'C9'], 'W', ['E', 'F', 'C9']),
    (['E', 'W', 'F'], 'C9', ['E', 'W', 'F']),
])
def test_enable(ignore_list, code, expected_list):
    """Verify that enabling a plugin removes it from the ignore list."""
    options = mock.Mock(ignore=ignore_list)
    optmanager = mock.Mock()
    plugin = manager.Plugin(code, mock.Mock())

    plugin.enable(optmanager, options)

    assert options.ignore == expected_list


def test_enable_without_providing_parsed_options():
    """Verify that enabling a plugin removes it from the ignore list."""
    optmanager = mock.Mock()
    plugin = manager.Plugin('U4', mock.Mock())

    plugin.enable(optmanager)

    optmanager.remove_from_default_ignore.assert_called_once_with(['U4'])