# Unit Tests: TileService

**Task**: AZ-286_tile_service_tests
**Name**: Unit tests: TileService (download, cache, dedup)
**Complexity**: 3 points
**Dependencies**: AZ-285
**Component**: Blackbox Tests
**Tracker**: AZ-286
**Epic**: AZ-284

## Scenarios

- BT-01: Tile download — mock ISatelliteDownloader.DownloadSingleTileAsync returns tile info; verify TileService stores it via ITileRepository.InsertAsync
- BT-02: Cache reuse — mock ITileRepository.GetTilesByRegionAsync returns existing tile; verify ISatelliteDownloader receives existing tiles to skip
- BT-N01: Invalid coordinates — verify appropriate error handling for out-of-range lat/lon
- BT-N02: Invalid zoom level — verify GoogleMapsDownloaderV2 rejects zoom levels outside allowed range

## Test Data

Coordinates from `input_data/test_coordinates.md`: lat=47.461747, lon=37.647063, zoom=18

## Expected Results

Per `input_data/expected_results/results_report.md`: tile with zoomLevel=18, tileSizePixels=256, imageType="jpg", non-empty filePath

## Acceptance Criteria

AC-1: All 4 scenarios have passing tests
AC-2: ISatelliteDownloader is mocked (no real Google Maps calls)
AC-3: Tests verify both happy path and error paths