rippr/test/tile_cache_test.dart

import 'dart:io';
import 'dart:typed_data';

import 'package:flutter_test/flutter_test.dart';
import 'package:rippr/src/tiles/tile_cache.dart';
import 'package:rippr/src/tiles/tile_math.dart';

void main() {
  late Directory tempDir;
  late FileTileCache cache;

  setUp(() async {
    tempDir = await Directory.systemTemp.createTemp('rippr_tile_cache_test_');
  });

  tearDown(() async {
    if (tempDir.existsSync()) tempDir.deleteSync(recursive: true);
  });

  Uint8List bytesOfSize(int n) => Uint8List.fromList(List.filled(n, 1));

  test('a stored tile round-trips', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    const key = TileKey(12, 100, 200);

    await cache.put(key, bytesOfSize(50));
    final read = await cache.get(key);

    expect(read, isNotNull);
    expect(read!.length, 50);
  });

  test('a tile never written is a miss, not an error', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    expect(await cache.get(const TileKey(1, 1, 1)), isNull);
  });

  test('sizeBytes reflects everything stored', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    await cache.put(const TileKey(1, 0, 0), bytesOfSize(100));
    await cache.put(const TileKey(1, 0, 1), bytesOfSize(200));

    expect(await cache.sizeBytes(), 300);
  });

  test('eviction at the cap removes the least-recently-used tile first', () async {
    // Room for two 100-byte tiles at a time.
    cache = FileTileCache(directory: tempDir, maxBytes: 200);
    const a = TileKey(1, 0, 0);
    const b = TileKey(1, 0, 1);
    const c = TileKey(1, 0, 2);

    await cache.put(a, bytesOfSize(100));
    await cache.put(b, bytesOfSize(100));
    // Touch `a` so `b` becomes the least-recently-used.
    await cache.get(a);
    await cache.put(c, bytesOfSize(100));

    expect(await cache.get(a), isNotNull, reason: 'recently touched, must survive');
    expect(await cache.get(b), isNull, reason: 'least-recently-used, must be evicted');
    expect(await cache.get(c), isNotNull, reason: 'just written, must survive');
    expect(await cache.sizeBytes(), lessThanOrEqualTo(200));
  });

  test('the cache never exceeds its cap after many writes', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 500);
    for (var i = 0; i < 20; i++) {
      await cache.put(TileKey(1, i, 0), bytesOfSize(100));
    }
    expect(await cache.sizeBytes(), lessThanOrEqualTo(500));
  });

  test('clear removes every tile and resets size to zero', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    await cache.put(const TileKey(1, 0, 0), bytesOfSize(100));
    await cache.put(const TileKey(1, 0, 1), bytesOfSize(100));

    await cache.clear();

    expect(await cache.sizeBytes(), 0);
    expect(await cache.get(const TileKey(1, 0, 0)), isNull);
  });

  test('a cache re-opened over the same directory sees what was stored', () async {
    cache = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    await cache.put(const TileKey(5, 10, 10), bytesOfSize(64));

    final reopened = FileTileCache(directory: tempDir, maxBytes: 1024 * 1024);
    expect(await reopened.get(const TileKey(5, 10, 10)), isNotNull);
    expect(await reopened.sizeBytes(), 64);
  });

  test('a tile cached under one provider directory is not served from another '
      '(UI-09)', () async {
    // `TileKey` carries no provider identity -- (z, x, y) alone can't tell an OSM tan
    // tile from a CARTO dark one at the same coordinates. `tileCacheProvider` (see
    // app/providers.dart) relies entirely on giving each tile source its own
    // subdirectory to prevent a switch from silently serving stale, visually-mismatched
    // tiles. This proves that isolation actually holds at the `FileTileCache` level.
    final osm = FileTileCache(
      directory: Directory('${tempDir.path}/osm'),
      maxBytes: 1024 * 1024,
    );
    final cartoDark = FileTileCache(
      directory: Directory('${tempDir.path}/carto_dark_v1'),
      maxBytes: 1024 * 1024,
    );

    await osm.put(const TileKey(5, 10, 10), bytesOfSize(64));

    expect(await cartoDark.get(const TileKey(5, 10, 10)), isNull,
        reason: 'a tile cached under the old provider must not leak into the new one');
  });
}