testing library

Test helpers for the catalog the generator produced.

A generated CatalogItem is a contract with a model: these components exist, they take these properties, and this is what the app does with them. The schema half of that contract is checked at build time. This library checks the other half — what the rendered component exposes to the person using it — by recording the semantics of each item's example and failing when they change.

The recorded file is the same shape A2UI's rendering cases are written in, so it doubles as the answer to "what can the model make this app announce", which is not visible from a Dart diff.

// test/genui_semantics_test.dart
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:genui_gen/testing.dart';
import 'package:my_app/genui_catalog.g.dart';

void main() {
  testWidgets('the catalog exposes what it did before', (tester) async {
    final recorded = <String, List<GenUiSemanticNode>>{};
    for (final item in genUiCatalog.items) {
      final handle = tester.ensureSemantics();
      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            body: GenUiExampleSurface(catalog: genUiCatalog, item: item),
          ),
        ),
      );
      await tester.pumpAndSettle();
      recorded[item.name] = genUiRenderedSemantics();
      handle.dispose();
    }

    expect(
      genUiSemanticsGolden(recorded, File('test/genui_semantics.json')),
      isNull,
    );
  });
}

genUiSemanticsAudit reads the same recording and reports what a person using a screen reader could not work with: a control with no name, a component that reaches assistive technology as nothing at all, two buttons that announce themselves identically. genUiCatalogWeight answers a different question with the same catalog: how much of every prompt each component takes up.

genUiCatalogDiff answers the other half of the question, about the contract rather than the rendering: what changed for the model between two versions of the catalog, and whether a message composed against the old one can still be wrong.

Record the file the first time, and after a deliberate change, by setting GENUI_UPDATE_GOLDENS=1:

GENUI_UPDATE_GOLDENS=1 flutter test test/genui_semantics_test.dart