lib/web_ui/test/ui/paragraph_builder_test.dart

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:test/bootstrap/browser.dart';
import 'package:test/test.dart';
import 'package:ui/ui.dart';

import '../common/test_initialization.dart';

void main() {
  internalBootstrapBrowserTest(() => testMain);
}

Future<void> testMain() async {
  setUpUnitTests(
    withImplicitView: true,
    emulateTesterEnvironment: false,
    setUpTestViewDimensions: false,
  );

  test('Should be able to build and layout a paragraph', () {
    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
    builder.addText('Hello');
    final Paragraph paragraph = builder.build();
    expect(paragraph, isNotNull);

    paragraph.layout(const ParagraphConstraints(width: 800.0));
    expect(paragraph.width, isNonZero);
    expect(paragraph.height, isNonZero);
  });

  test('the presence of foreground style should not throw', () {
    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
    builder.pushStyle(TextStyle(
      foreground: Paint()..color = const Color(0xFFABCDEF),
    ));
    builder.addText('hi');

    expect(() => builder.build(), returnsNormally);
  });

  test('getWordBoundary respects position affinity', () {
    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
    builder.addText('hello world');

    final Paragraph paragraph = builder.build();
    paragraph.layout(const ParagraphConstraints(width: double.infinity));

    final TextRange downstreamWordBoundary = paragraph.getWordBoundary(const TextPosition(
      offset: 5,
    ));
    expect(downstreamWordBoundary, const TextRange(start: 5, end: 6));

    final TextRange upstreamWordBoundary = paragraph.getWordBoundary(const TextPosition(
      offset: 5,
      affinity: TextAffinity.upstream,
    ));
    expect(upstreamWordBoundary, const TextRange(start: 0, end: 5));
  });

  test('getLineBoundary at the last character position gives correct results', () {
    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
    builder.addText('hello world');

    final Paragraph paragraph = builder.build();
    paragraph.layout(const ParagraphConstraints(width: double.infinity));

    final TextRange lineBoundary = paragraph.getLineBoundary(const TextPosition(
      offset: 11,
    ));
    expect(lineBoundary, const TextRange(start: 0, end: 11));
  });

  test('build and layout a paragraph with an empty addText', () {
    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
    builder.addText('');
    final Paragraph paragraph = builder.build();
    expect(
      () => paragraph.layout(const ParagraphConstraints(width: double.infinity)),
      returnsNormally,
    );
  });
}