Files
minstrel/flutter_client/test/cache/cache_first_test.dart
T

83 lines
2.8 KiB
Dart

import 'dart:async';
import 'package:flutter_test/flutter_test.dart';
import 'package:minstrel/cache/cache_first.dart';
void main() {
test('non-empty drift emission passes through toResult', () async {
final controller = StreamController<List<int>>();
final results = cacheFirst<int, int>(
driftStream: controller.stream,
fetchAndPopulate: () async => fail('should not fetch when rows present'),
toResult: (rows) => rows.fold<int>(0, (a, b) => a + b),
isOnline: () async => true,
);
final firstFuture = results.first;
controller.add([1, 2, 3]);
expect(await firstFuture, 6);
await controller.close();
});
test('empty drift emission + online triggers fetchAndPopulate', () async {
final controller = StreamController<List<int>>();
var fetchCalled = 0;
final results = cacheFirst<int, int>(
driftStream: controller.stream,
fetchAndPopulate: () async {
fetchCalled++;
controller.add([42]); // simulate populate causing re-emission
},
toResult: (rows) => rows.fold<int>(0, (a, b) => a + b),
isOnline: () async => true,
);
// Post-coldFetchAttempted guard, cacheFirst yields the current
// (still-empty) rows after the fetch returns, so the stream
// never hangs when populate is a no-op for this filter. The
// simulated drift re-emit then yields the populated rows.
// Capture the Future *before* feeding the controller so the
// listener is subscribed when the first add() lands.
final emissionsFuture = results.take(2).toList();
controller.add([]);
final emissions = await emissionsFuture;
expect(emissions, [0, 42]);
expect(fetchCalled, 1);
await controller.close();
});
test('empty drift + offline yields empty result without fetch', () async {
final controller = StreamController<List<int>>();
var fetchCalled = 0;
final results = cacheFirst<int, int>(
driftStream: controller.stream,
fetchAndPopulate: () async {
fetchCalled++;
},
toResult: (rows) => rows.fold<int>(0, (a, b) => a + b),
isOnline: () async => false,
);
final firstFuture = results.first;
controller.add([]);
expect(await firstFuture, 0);
expect(fetchCalled, 0);
await controller.close();
});
test('REST failure falls through to empty result', () async {
final controller = StreamController<List<int>>();
final results = cacheFirst<int, int>(
driftStream: controller.stream,
fetchAndPopulate: () async => throw Exception('REST 500'),
toResult: (rows) => rows.fold<int>(0, (a, b) => a + b),
isOnline: () async => true,
);
final firstFuture = results.first;
controller.add([]);
expect(await firstFuture, 0);
await controller.close();
});
}