test: stabilize deterministic integration coverage
This commit is contained in:
edde746
+188
-112
@@ -1,4 +1,5 @@
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import 'dart:async';
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import 'package:fake_async/fake_async.dart';
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import 'package:flutter_test/flutter_test.dart';
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import 'package:plezy/utils/endpoint_race.dart';
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@@ -30,145 +31,220 @@ void main() {
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);
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}
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Future<_Result> resultAfter(String url, Duration delay, {required bool ok}) async {
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await Future<void>.delayed(delay);
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return (url: url, ok: ok);
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}
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test('healthy cached endpoint wins within the head start without racing', () {
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fakeAsync((async) {
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final probeCounts = <String, int>{};
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final selections = <EndpointRaceSelection<String, _Result>>[];
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late Completer<_Result> cachedGate;
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test('healthy cached endpoint wins within the head start without racing', () async {
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final probeCounts = <String, int>{};
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final selections = await race(
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candidates: ['a', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return resultAfter(url, const Duration(milliseconds: 10), ok: true);
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},
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).toList();
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race(
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candidates: ['a', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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final gate = Completer<_Result>();
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if (url == 'cached') cachedGate = gate;
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return gate.future;
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},
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).listen(selections.add);
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async.flushMicrotasks();
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expect(selections.first.phase, EndpointRacePhase.first);
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expect(selections.first.candidate, 'cached');
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expect(selections.first.fromPreferred, isTrue);
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expect(probeCounts['cached'], 1);
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// The race never started; only the phase-2 measure touches other URLs.
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expect(probeCounts.containsKey('a'), isFalse);
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expect(probeCounts, {'cached': 1});
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cachedGate.complete((url: 'cached', ok: true));
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async.flushMicrotasks();
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expect(selections.first.phase, EndpointRacePhase.first);
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expect(selections.first.candidate, 'cached');
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expect(selections.first.fromPreferred, isTrue);
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expect(probeCounts.containsKey('a'), isFalse);
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async.elapse(headStart);
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async.flushMicrotasks();
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});
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});
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test('stale-slow cached endpoint overlaps the race instead of serially blocking it', () async {
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final probeCounts = <String, int>{};
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final stopwatch = Stopwatch()..start();
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final firstTimes = <int>[];
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final selections = <EndpointRaceSelection<String, _Result>>[];
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await for (final selection in race(
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candidates: ['fast', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return resultAfter(
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url,
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url == 'cached' ? const Duration(milliseconds: 250) : const Duration(milliseconds: 10),
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ok: url != 'cached',
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);
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},
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)) {
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selections.add(selection);
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firstTimes.add(stopwatch.elapsedMilliseconds);
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}
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test('stale-slow cached endpoint overlaps the race instead of serially blocking it', () {
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fakeAsync((async) {
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final probeCounts = <String, int>{};
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final selections = <EndpointRaceSelection<String, _Result>>[];
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late Completer<_Result> cachedGate;
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late Completer<_Result> fastGate;
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expect(selections.first.candidate, 'fast');
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expect(selections.first.fromPreferred, isFalse);
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// Emitted shortly after the head start — not after the cached probe's
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// full budget (the pre-change serial behavior).
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expect(firstTimes.first, lessThan(200));
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// The pending cached probe was merged into the race, not re-fired.
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expect(probeCounts['cached'], 1);
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race(
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candidates: ['fast', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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final gate = Completer<_Result>();
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if (url == 'cached') {
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cachedGate = gate;
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} else {
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fastGate = gate;
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}
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return gate.future;
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},
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).listen(selections.add);
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async.flushMicrotasks();
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// Let the still-pending cached probe finish inside the test body.
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await Future<void>.delayed(const Duration(milliseconds: 300));
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expect(probeCounts, {'cached': 1});
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async.elapse(headStart - const Duration(milliseconds: 1));
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async.flushMicrotasks();
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expect(probeCounts, {'cached': 1});
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async.elapse(const Duration(milliseconds: 1));
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async.flushMicrotasks();
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expect(probeCounts, {'cached': 1, 'fast': 1});
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fastGate.complete((url: 'fast', ok: true));
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async.flushMicrotasks();
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expect(selections.first.phase, EndpointRacePhase.first);
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expect(selections.first.candidate, 'fast');
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expect(selections.first.fromPreferred, isFalse);
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expect(probeCounts['cached'], 1);
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cachedGate.complete((url: 'cached', ok: false));
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async.flushMicrotasks();
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});
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});
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test('cached endpoint that answers after the head start still wins when first', () async {
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final probeCounts = <String, int>{};
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final selections = await race(
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candidates: ['slow', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return resultAfter(
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url,
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url == 'cached' ? const Duration(milliseconds: 120) : const Duration(milliseconds: 350),
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ok: true,
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);
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},
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).toList();
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test('cached endpoint that answers after the head start still wins when first', () {
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fakeAsync((async) {
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final probeCounts = <String, int>{};
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final selections = <EndpointRaceSelection<String, _Result>>[];
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late Completer<_Result> cachedGate;
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late Completer<_Result> slowGate;
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expect(selections.first.candidate, 'cached');
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expect(selections.first.fromPreferred, isTrue);
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expect(probeCounts['cached'], 1);
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race(
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candidates: ['slow', 'cached'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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final gate = Completer<_Result>();
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if (url == 'cached') {
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cachedGate = gate;
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} else {
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slowGate = gate;
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}
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return gate.future;
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},
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).listen(selections.add);
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async.flushMicrotasks();
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await Future<void>.delayed(const Duration(milliseconds: 400));
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expect(probeCounts, {'cached': 1});
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async.elapse(headStart);
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async.flushMicrotasks();
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expect(probeCounts, {'cached': 1, 'slow': 1});
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cachedGate.complete((url: 'cached', ok: true));
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async.flushMicrotasks();
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expect(selections.first.candidate, 'cached');
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expect(selections.first.fromPreferred, isTrue);
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expect(probeCounts['cached'], 1);
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slowGate.complete((url: 'slow', ok: true));
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async.flushMicrotasks();
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});
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});
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test('cached endpoint failing within the head start falls back to a fresh race', () async {
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final probeCounts = <String, int>{};
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final selections = await race(
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candidates: ['cached', 'alt'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return resultAfter(url, const Duration(milliseconds: 10), ok: url == 'alt');
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},
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).toList();
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test('cached endpoint failing within the head start falls back to a fresh race', () {
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fakeAsync((async) {
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final probeCounts = <String, int>{};
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final selections = <EndpointRaceSelection<String, _Result>>[];
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final cachedGates = <Completer<_Result>>[];
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late Completer<_Result> altGate;
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expect(selections.first.candidate, 'alt');
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expect(selections.first.fromPreferred, isFalse);
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// Fast-fail keeps today's semantics: the cached URL re-races as a
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// normal candidate (one probe up front, one inside the race).
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expect(probeCounts['cached'], 2);
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race(
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candidates: ['cached', 'alt'],
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preferred: 'cached',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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final gate = Completer<_Result>();
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if (url == 'cached') {
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cachedGates.add(gate);
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} else {
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altGate = gate;
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}
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return gate.future;
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},
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).listen(selections.add);
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async.flushMicrotasks();
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cachedGates.single.complete((url: 'cached', ok: false));
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async.flushMicrotasks();
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expect(probeCounts, {'cached': 2, 'alt': 1});
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cachedGates.last.complete((url: 'cached', ok: false));
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altGate.complete((url: 'alt', ok: true));
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async.flushMicrotasks();
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expect(selections.first.candidate, 'alt');
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expect(selections.first.fromPreferred, isFalse);
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expect(probeCounts['cached'], 2);
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async.elapse(headStart);
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async.flushMicrotasks();
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});
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});
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test('preferred URL not among candidates skips the cached probe entirely', () async {
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final probeCounts = <String, int>{};
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final selections = await race(
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candidates: ['a', 'b'],
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preferred: 'custom-url',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return resultAfter(url, const Duration(milliseconds: 10), ok: url == 'a');
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},
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).toList();
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test('preferred URL not among candidates skips the cached probe entirely', () {
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fakeAsync((async) {
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final probeCounts = <String, int>{};
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final selections = <EndpointRaceSelection<String, _Result>>[];
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final gates = <String, Completer<_Result>>{};
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expect(selections.first.candidate, 'a');
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expect(selections.first.fromPreferred, isFalse);
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expect(probeCounts.containsKey('custom-url'), isFalse);
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race(
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candidates: ['a', 'b'],
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preferred: 'custom-url',
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probe: (url) {
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probeCounts[url] = (probeCounts[url] ?? 0) + 1;
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return (gates[url] = Completer<_Result>()).future;
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},
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).listen(selections.add);
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async.flushMicrotasks();
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expect(probeCounts.containsKey('custom-url'), isFalse);
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gates['a']!.complete((url: 'a', ok: true));
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gates['b']!.complete((url: 'b', ok: false));
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async.flushMicrotasks();
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expect(selections.first.candidate, 'a');
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expect(selections.first.fromPreferred, isFalse);
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});
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});
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test('emits nothing when every candidate fails', () async {
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final selections = await race(
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candidates: ['a', 'b'],
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preferred: 'a',
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probe: (url) => resultAfter(url, const Duration(milliseconds: 10), ok: false),
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probe: (url) async => (url: url, ok: false),
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).toList();
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expect(selections, isEmpty);
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});
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test('phase 2 still promotes the selector-best endpoint', () async {
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final selections = await race(
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candidates: ['quick', 'better'],
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probe: (url) => resultAfter(
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url,
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url == 'quick' ? const Duration(milliseconds: 10) : const Duration(milliseconds: 80),
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ok: true,
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),
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measure: (url) async => (url: url, ok: true),
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selectBest: (results) => 'better',
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).toList();
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test('phase 2 still promotes the selector-best endpoint', () {
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fakeAsync((async) {
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final selections = <EndpointRaceSelection<String, _Result>>[];
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final gates = <String, Completer<_Result>>{};
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expect(selections, hasLength(2));
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expect(selections.first.phase, EndpointRacePhase.first);
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expect(selections.first.candidate, 'quick');
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expect(selections.last.phase, EndpointRacePhase.best);
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expect(selections.last.candidate, 'better');
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race(
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candidates: ['quick', 'better'],
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probe: (url) => (gates[url] = Completer<_Result>()).future,
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measure: (url) async => (url: url, ok: true),
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selectBest: (results) => 'better',
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).listen(selections.add);
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async.flushMicrotasks();
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gates['quick']!.complete((url: 'quick', ok: true));
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async.flushMicrotasks();
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gates['better']!.complete((url: 'better', ok: true));
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async.flushMicrotasks();
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expect(selections, hasLength(2));
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expect(selections.first.phase, EndpointRacePhase.first);
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expect(selections.first.candidate, 'quick');
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expect(selections.last.phase, EndpointRacePhase.best);
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expect(selections.last.candidate, 'better');
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});
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});
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}
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