Add comprehensive unit tests with Swift Testing framework

[jogi]

Summary

Comprehensive test suite for GTFSImporter achieving 90.82% code coverage using Swift Testing framework.

• ✅ 43 tests in 18 suites, all passing
• ✅ 90.82% code coverage (exceeds 90% target)
• ✅ Migrated from XCTest to Swift Testing framework
• ✅ Tests use real VTA GTFS data - no synthetic INSERT statements
• ✅ No mocking - uses real database and file operations

Test Organization

Utility Tests (8 tests)

• StringExtensionTests: Time sanitization for overnight GTFS times (≥24:00:00)
• ConsoleTests: ANSI color output validation
• StopTimeInterpolatorTests: Distance-based time interpolation using Haversine formula

Entity Importing Tests (9 tests, 9 suites)

Tests for all GTFS entity types using real VTA production data:

• Agency, Calendar, Route, Stop, Trip, etc.
• Validates CSV parsing via actual importer (not INSERT statements)
• Uses small real dataset (5 trips, 130 stop_times, 26 stops)

Integration Tests (26 tests, 4 suites)

• ImporterTests: Full import orchestration, table creation, foreign key relationships
• StopRouteTests: Stop-route relationship building
• EndToEndImportTests: Complete workflow validation, data consistency checks
• PerformanceTests: Import timing and efficiency benchmarks

All tests use the actual importer with real GTFS data from VTA, ensuring tests validate the complete import pipeline.

Test Data

Small Real Dataset (Tests/gtfs-importerTests/testData/small/):

• Extracted from production VTA GTFS data
• 5 trips, 130 stop_times, 26 stops, 958 shape points
• Maintains full referential integrity
• Fast imports (~0.1s) for integration tests

Full Real Dataset (Tests/gtfs-importerTests/testData/):

• Complete VTA GTFS feed (~428K stop_times)
• Used for performance and comprehensive validation tests

Code Coverage by File

File	Coverage
StopTimeInterpolator.swift	96.76%
StopRoute.swift	96.55%
Console.swift	93.75%
StopTime+Importing.swift	89.33%
Importer.swift	82.72%
String.swift	100.00%
Simple importers	100.00%
Overall	90.82%

Key Features

• Swift Testing framework: Modern @Suite and @Test annotations
• Real data testing: No INSERT statements - uses actual CSV imports
• Test utilities:
  • TestDataHelper: Manages real and synthetic GTFS datasets
  • DatabaseTestHelper: Database creation and cleanup
  • TemporaryFileHelper: File system test isolation
• Real operations: No mocking - tests use actual databases and file I/O

Running Tests

⚠️ IMPORTANT: Tests must be run with --no-parallel flag:

swift test --no-parallel

This is required because:

• The Importer class hardcodes database path to "./gtfs.db"
• Integration test suites can run in parallel, causing database locking conflicts
• The .serialized trait only applies within a suite, not across suites

Changes

Added:

• 20 test files organized by category (Utility, Importing, Integration)
• 3 test utility classes
• TestTags.swift for test organization
• Real VTA GTFS test data (small and full datasets)

Removed:

• XCTestManifests.swift (not needed with Swift Testing)
• LinuxMain.swift (SPM auto-discovery since Swift 5.4)
• gtfs_importerTests.swift (placeholder test)
• Synthetic INSERT-based test fixtures

All tests passing ✅

🤖 Generated with Claude Code

[jogi]

Test Refactoring Update

Refactored all tests to use real GTFS data instead of synthetic INSERT statements, addressing the concerns about test authenticity.

Changes Made

❌ Before: Tests used direct SQL INSERT statements

// BAD - Bypassed the importer completely
try db.execute(sql: "INSERT INTO stops ...")
try db.execute(sql: "INSERT INTO routes ...")

✅ After: Tests use the actual importer with real data

// GOOD - Tests the complete import pipeline
let importer = Importer(path: TestDataHelper.smallRealTestDataPath())
try importer.importAllFiles()

New Test Data

Created Tests/gtfs-importerTests/testData/small/ - a small subset extracted from real VTA production data:

• 5 trips (Blue Line)
• 130 stop_times (real timepoint data)
• 26 stops (actual VTA station locations)
• 958 shape points (geographic paths)
• Full referential integrity maintained
• Fast imports (~0.1s vs 60s for full dataset)

Test Organization

Test Data Tiers:

1. Inline CSV - Edge cases only (overnight times, malformed data)
2. Small real (testData/small/) - Integration tests
3. Full real (testData/) - Performance tests

Infrastructure Fixes

• ✅ Moved testData/ into test target directory
• ✅ Added test resources to Package.swift
• ✅ Updated TestDataHelper to use Bundle.module
• ✅ All 43 tests passing with real production data

Test Results

✅ 43 tests in 18 suites - All passing
⏱️  6.8 seconds

Tests now validate the actual CSV parsing and import pipeline with real GTFS data, ensuring they catch real-world issues.