test: Add comprehensive test suite for database sync functionality

[saber04414]

Description

This PR adds a comprehensive unit test suite for the database sync functionality to ensure proper schema comparison, table operations, column management, and database synchronization for both MySQL and SQLite.

Changes

• Enhanced: test/test_db_sync.py - Added comprehensive test suite to existing file

Test Coverage

✅ Test Case 1: Schema Comparison

• Tests schema comparison when schemas are identical
• Tests detection of added tables in ORM
• Tests detection of deleted tables from ORM
• Tests detection of added columns
• Tests detection of deleted columns
• Tests detection of modified column types
• Tests multiple changes in a single table (added, deleted, modified columns)

✅ Test Case 2: Table Creation

• Verifies tables can be created from ORM models
• Tests that created tables appear in database schema
• Tests table structure matches ORM model
• Tests creation of multiple tables
• Tests that tables don't interfere with each other

✅ Test Case 3: Column Addition

• Tests that new columns can be added to existing tables
• Verifies added columns appear in database schema
• Tests that existing data is preserved when adding columns
• Tests column addition with various data types

✅ Test Case 4: Column Modification

• Tests detection of column type modifications
• Verifies modified columns are identified in diff
• Tests column modification with different type changes
• Tests that modification detection works correctly

✅ Test Case 5: Column Deletion

• Tests detection of column deletions
• Verifies deleted columns appear in diff
• Tests column deletion detection accuracy
• Tests handling of deleted columns in schema comparison

✅ Test Case 6: MySQL Sync

• Tests MySQL sync for table creation
• Tests MySQL engine creation and connection
• Tests error handling during MySQL sync
• Tests schema comparison with MySQL
• Uses mocking to avoid requiring actual MySQL connection

✅ Test Case 7: SQLite Sync

• Tests SQLite sync for table creation
• Tests SQLite engine creation
• Tests schema comparison with SQLite
• Tests file-based SQLite database operations
• Tests in-memory SQLite database operations

Additional Test Cases

• get_db_schema: Tests database schema retrieval
• get_orm_schema: Tests ORM schema retrieval
• print_diff: Tests diff printing with no differences
• print_diff: Tests diff printing with various differences
• sync_database: Tests database synchronization function

Additional Features

• In-Memory Database Testing: Uses SQLite in-memory databases for fast, isolated testing
• File-Based Testing: Tests with temporary file-based SQLite databases
• Comprehensive Comments: Extensive inline comments and docstrings for easy understanding
• Clear Structure: Well-organized test methods with clear section separators
• Mocking: Proper use of mocks to avoid requiring actual database connections
• Edge Case Coverage: Tests various schema change scenarios

Testing

Run the test suite with:
python -m unittest test.test_db_syncOr directly:
python test/test_db_sync.py## Notes

• All tests use SQLite in-memory or temporary file databases for fast execution
• Tests are isolated and don't affect actual database connections
• MySQL tests use mocking to avoid requiring actual MySQL server
• Code includes extensive comments and blank lines for readability
• Follows the project's code style and licensing requirements
• Original functionality is preserved - tests are added to existing file
• Tests cover all sync operations: comparison, creation, addition, modification, deletion

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