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Testing React Native Command Recognition Implementation in thefuck

This test suite validates the behavior of React Native command recognition and correction functionality in thefuck utility. It ensures proper handling of unrecognized commands and provides appropriate command suggestions.

Test Coverage Overview

The test suite provides comprehensive coverage for React Native command recognition and correction.

Key areas tested include:

Command matching for invalid React Native commands
Non-matching scenarios for valid commands
Command correction suggestions
Edge cases with similar command patterns

Implementation Analysis

The testing approach uses pytest’s parametrize feature to efficiently test multiple input scenarios.

Technical implementation details:

Mock handling of command outputs
BytesIO simulation of stdout
Parametrized test cases for different command variations

Technical Details

Testing infrastructure includes:

pytest framework
Mock objects for command simulation
BytesIO for stdout handling
Command type definitions from thefuck.types
Parametrized test decorators

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Separation of matching and correction logic
Comprehensive positive and negative test cases
Efficient test parameterization
Mock usage for external dependencies
Clear test case organization

nvbn/thefuck

tests/rules/test_react_native_command_unrecognized.py

            
import pytest
from io import BytesIO
from thefuck.rules.react_native_command_unrecognized import match, \
    get_new_command
from thefuck.types import Command

output = "Unrecognized command '{}'".format

stdout = b'''
Scanning 615 folders for symlinks in /home/nvbn/work/zcho/BookkaWebView/node_modules (6ms)

  Usage: react-native [options] [command]


  Options:

    -V, --version  output the version number
    -h, --help     output usage information


  Commands:

    start [options]                    starts the webserver
    run-ios [options]                  builds your app and starts it on iOS simulator
    run-android [options]              builds your app and starts it on a connected Android emulator or device
    new-library [options]              generates a native library bridge
    bundle [options]                   builds the javascript bundle for offline use
    unbundle [options]                 builds javascript as "unbundle" for offline use
    eject [options]                    Re-create the iOS and Android folders and native code
    link [options] [packageName]       links all native dependencies (updates native build files)
    unlink [options] <packageName>     unlink native dependency
    install [options] <packageName>    install and link native dependencies
    uninstall [options] <packageName>  uninstall and unlink native dependencies
    upgrade [options]                  upgrade your app's template files to the latest version; run this after updating the react-native version in your package.json and running npm install
    log-android [options]              starts adb logcat
    log-ios [options]                  starts iOS device syslog tail
'''


@pytest.mark.parametrize('command', [
    Command('react-native star', output('star')),
    Command('react-native android-logs', output('android-logs'))])
def test_match(command):
    assert match(command)


@pytest.mark.parametrize('command', [
    Command('gradle star', output('star')),
    Command('react-native start', '')])
def test_not_match(command):
    assert not match(command)


@pytest.mark.parametrize('command, result', [
    (Command('react-native star', output('star')),
     'react-native start'),
    (Command('react-native logsandroid -f', output('logsandroid')),
     'react-native log-android -f')])
def test_get_new_command(mocker, command, result):
    patch = mocker.patch(
        'thefuck.rules.react_native_command_unrecognized.Popen')
    patch.return_value.stdout = BytesIO(stdout)
    assert get_new_command(command)[0] == result