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Testing Configuration Management System in TheFuck

This test suite validates the configuration handling and settings management functionality in TheFuck, a command-line tool for correcting mistyped console commands. The tests ensure proper initialization, loading, and processing of user settings from different sources including environment variables and configuration files.

Test Coverage Overview

The test suite provides comprehensive coverage of configuration management:

Default settings initialization and validation
Configuration loading from files with custom settings
Environment variable processing and override behavior
Command-line argument handling
Settings file initialization and creation
User directory path resolution

Implementation Analysis

The testing approach employs pytest fixtures and mocking to isolate configuration components:

Implements class-based test organization for related test cases, uses pytest fixtures for dependency injection, and leverages mocker/Mock objects to simulate file operations and environment interactions. The tests verify both simple and complex configuration scenarios including DEFAULT settings inheritance.

Technical Details

Testing tools and setup:

pytest framework with fixtures and parametrize
mock library for object mocking
six for Python 2/3 compatibility
Custom fixtures: load_source, settings
Environment variable manipulation
File system interaction testing

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Demonstrates proper test isolation through fixtures, comprehensive edge case coverage, clear test case organization, and effective use of parametrized testing. The code maintains high readability with descriptive test names and logical grouping of related test cases into classes.

nvbn/thefuck

tests/test_conf.py

            
import pytest
import six
import os
from mock import Mock
from thefuck import const


@pytest.fixture
def load_source(mocker):
    return mocker.patch('thefuck.conf.load_source')


def test_settings_defaults(load_source, settings):
    load_source.return_value = object()
    settings.init()
    for key, val in const.DEFAULT_SETTINGS.items():
        assert getattr(settings, key) == val


class TestSettingsFromFile(object):
    def test_from_file(self, load_source, settings):
        load_source.return_value = Mock(rules=['test'],
                                        wait_command=10,
                                        require_confirmation=True,
                                        no_colors=True,
                                        priority={'vim': 100},
                                        exclude_rules=['git'])
        settings.init()
        assert settings.rules == ['test']
        assert settings.wait_command == 10
        assert settings.require_confirmation is True
        assert settings.no_colors is True
        assert settings.priority == {'vim': 100}
        assert settings.exclude_rules == ['git']

    def test_from_file_with_DEFAULT(self, load_source, settings):
        load_source.return_value = Mock(rules=const.DEFAULT_RULES + ['test'],
                                        wait_command=10,
                                        exclude_rules=[],
                                        require_confirmation=True,
                                        no_colors=True)
        settings.init()
        assert settings.rules == const.DEFAULT_RULES + ['test']


@pytest.mark.usefixtures('load_source')
class TestSettingsFromEnv(object):
    def test_from_env(self, os_environ, settings):
        os_environ.update({'THEFUCK_RULES': 'bash:lisp',
                           'THEFUCK_EXCLUDE_RULES': 'git:vim',
                           'THEFUCK_WAIT_COMMAND': '55',
                           'THEFUCK_REQUIRE_CONFIRMATION': 'true',
                           'THEFUCK_NO_COLORS': 'false',
                           'THEFUCK_PRIORITY': 'bash=10:lisp=wrong:vim=15',
                           'THEFUCK_WAIT_SLOW_COMMAND': '999',
                           'THEFUCK_SLOW_COMMANDS': 'lein:react-native:./gradlew',
                           'THEFUCK_NUM_CLOSE_MATCHES': '359',
                           'THEFUCK_EXCLUDED_SEARCH_PATH_PREFIXES': '/media/:/mnt/'})
        settings.init()
        assert settings.rules == ['bash', 'lisp']
        assert settings.exclude_rules == ['git', 'vim']
        assert settings.wait_command == 55
        assert settings.require_confirmation is True
        assert settings.no_colors is False
        assert settings.priority == {'bash': 10, 'vim': 15}
        assert settings.wait_slow_command == 999
        assert settings.slow_commands == ['lein', 'react-native', './gradlew']
        assert settings.num_close_matches == 359
        assert settings.excluded_search_path_prefixes == ['/media/', '/mnt/']

    def test_from_env_with_DEFAULT(self, os_environ, settings):
        os_environ.update({'THEFUCK_RULES': 'DEFAULT_RULES:bash:lisp'})
        settings.init()
        assert settings.rules == const.DEFAULT_RULES + ['bash', 'lisp']


def test_settings_from_args(settings):
    settings.init(Mock(yes=True, debug=True, repeat=True))
    assert not settings.require_confirmation
    assert settings.debug
    assert settings.repeat


class TestInitializeSettingsFile(object):
    def test_ignore_if_exists(self, settings):
        settings_path_mock = Mock(is_file=Mock(return_value=True), open=Mock())
        settings.user_dir = Mock(joinpath=Mock(return_value=settings_path_mock))
        settings._init_settings_file()
        assert settings_path_mock.is_file.call_count == 1
        assert not settings_path_mock.open.called

    def test_create_if_doesnt_exists(self, settings):
        settings_file = six.StringIO()
        settings_path_mock = Mock(
            is_file=Mock(return_value=False),
            open=Mock(return_value=Mock(
                __exit__=lambda *args: None, __enter__=lambda *args: settings_file)))
        settings.user_dir = Mock(joinpath=Mock(return_value=settings_path_mock))
        settings._init_settings_file()
        settings_file_contents = settings_file.getvalue()
        assert settings_path_mock.is_file.call_count == 1
        assert settings_path_mock.open.call_count == 1
        assert const.SETTINGS_HEADER in settings_file_contents
        for setting in const.DEFAULT_SETTINGS.items():
            assert '# {} = {}
'.format(*setting) in settings_file_contents
        settings_file.close()


@pytest.mark.parametrize('legacy_dir_exists, xdg_config_home, result', [
    (False, '~/.config', '~/.config/thefuck'),
    (False, '/user/test/config/', '/user/test/config/thefuck'),
    (True, '~/.config', '~/.thefuck'),
    (True, '/user/test/config/', '~/.thefuck')])
def test_get_user_dir_path(mocker, os_environ, settings, legacy_dir_exists,
                           xdg_config_home, result):
    mocker.patch('thefuck.conf.Path.is_dir',
                 return_value=legacy_dir_exists)

    if xdg_config_home is not None:
        os_environ['XDG_CONFIG_HOME'] = xdg_config_home
    else:
        os_environ.pop('XDG_CONFIG_HOME', None)

    path = settings._get_user_dir_path().as_posix()
    assert path == os.path.expanduser(result)