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Testing Rails Migration Pending Detection in thefuck

This test suite validates the functionality of Rails migrations pending error handling in the thefuck command-line tool. It ensures proper detection and correction of scenarios where database migrations need to be run before executing Rails commands.

Test Coverage Overview

The test suite provides comprehensive coverage of Rails migration pending scenarios across different environments (development and test).

Key areas tested include:

Migration pending detection in development environment
Migration pending detection in test environment
Command correction for both environments
Negative test cases for non-matching scenarios

Implementation Analysis

The testing approach utilizes pytest’s parametrize feature to efficiently test multiple scenarios with different input commands and expected outputs. The implementation follows a behavior-driven pattern, testing both the matching logic and command generation separately.

Technical patterns include:

Parametrized test cases for different environments
Command object pattern for input/output handling
Explicit assertion-based validation

Technical Details

Testing tools and configuration:

pytest as the primary testing framework
Custom Command type for input structuring
Parametrized test decorators for multiple test cases
Mock output strings for different environments

Best Practices Demonstrated

The test suite exemplifies several testing best practices in Python unit testing. It demonstrates clear separation of concerns, thorough edge case coverage, and efficient test organization.

Notable practices include:

Isolated test cases for matching and command generation
Comprehensive environment coverage
Clear test case organization using parametrization
Explicit negative test cases

nvbn/thefuck

tests/rules/test_rails_migrations_pending.py

            
import pytest
from thefuck.rules.rails_migrations_pending import match, get_new_command
from thefuck.types import Command

output_env_development = '''
Migrations are pending. To resolve this issue, run:

        rails db:migrate RAILS_ENV=development
'''
output_env_test = '''
Migrations are pending. To resolve this issue, run:

        bin/rails db:migrate RAILS_ENV=test
'''


@pytest.mark.parametrize(
    "command",
    [
        Command("", output_env_development),
        Command("", output_env_test),
    ],
)
def test_match(command):
    assert match(command)


@pytest.mark.parametrize(
    "command",
    [
        Command("Environment data not found in the schema. To resolve this issue, run: 

", ""),
    ],
)
def test_not_match(command):
    assert not match(command)


@pytest.mark.parametrize(
    "command, new_command",
    [
        (Command("bin/rspec", output_env_development), "rails db:migrate RAILS_ENV=development && bin/rspec"),
        (Command("bin/rspec", output_env_test), "bin/rails db:migrate RAILS_ENV=test && bin/rspec"),
    ],
)
def test_get_new_command(command, new_command):
    assert get_new_command(command) == new_command