[Integration Test] TravelService

[adnanvaldes]

Overview

Add comprehensive integration tests for TravelService to verify database behavior, constraints, and data persistence beyond what unit tests cover.

Context

TravelService has specific SQLite constraints that need testing:

• CHECK(length(origin) = 3 AND origin = UPPER(origin))
• CHECK(length(destination) = 3 AND destination = UPPER(destination))
• UNIQUE(origin, destination, date)

Test Scenarios to Implement

1. Database Constraints Enforcement

• Test UNIQUE constraint prevents duplicate (origin, destination, date) at DB level
• Test CHECK constraint enforces 3-letter uppercase origin codes
• Test CHECK constraint enforces 3-letter uppercase destination codes
• Test constraint violations even when bypassing service validation

2. Data Type Conversion & Serialization

• Test date serialization roundtrip (Python date → SQLite TEXT → Python date)
• Test accepting ISO date strings ("2025-07-21")
• Test accepting date objects
• Test empty notes field (NULL vs "")

3. Transaction Behavior

• Test rollback when invalid country code provided
• Test rollback when duplicate travel added
• Test successful commit for valid travel
• Test multiple operations in single transaction

4. Query Behavior

• Test find() with origin filter
• Test find() with destination filter
• Test find() with date filter
• Test find() with multiple filters combined
• Test case handling (service uppercases input)

5. Schema & ID Management

• Verify travel table created with all constraints
• Test AUTOINCREMENT assigns sequential IDs
• Test ID doesn't reuse after deletion

6. Edge Cases

• Test with whitespace in country codes
• Test with lowercase country codes (should be uppercased)
• Test notes field with special characters and Unicode
• Test historical dates (1900-01-01) and future dates

Files to Create/Modify

• tests/integration/test_travel_service_integration.py

Acceptance Criteria

• All 20+ test scenarios implemented
• Tests use fake_db fixture
• All tests pass consistently

Notes

Existing integration tests in tests/integration/test_travel_service_integration.py cover basic scenarios. This issue tracks expansion to comprehensive database behavior testing.