Ocideck/test/code_preview_test.dart

import 'package:flutter/material.dart';
import 'package:flutter_highlight/flutter_highlight.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:ocideck/models/settings.dart';
import 'package:ocideck/models/slide.dart';
import 'package:ocideck/widgets/slides/slide_preview.dart';

Widget _host(Slide slide, ThemeProfile profile) {
  return Directionality(
    textDirection: TextDirection.ltr,
    child: Center(
      child: SizedBox(
        width: 800,
        height: 450,
        child: SlidePreviewWidget(slide: slide, themeProfile: profile),
      ),
    ),
  );
}

Color _hex(String hex) =>
    Color(int.parse(hex.substring(1), radix: 16) | 0xFF000000);

void main() {
  testWidgets('code slide paints the themed background colour', (tester) async {
    final slide = Slide.create(
      SlideType.code,
    ).copyWith(codeLanguage: 'dart', customMarkdown: 'void main() {}');
    const profile = ThemeProfile(
      codeBackgroundColor: '#000000',
      codeTextColor: '#33FF33',
    );

    await tester.pumpWidget(_host(slide, profile));
    await tester.pump();

    // The code panel uses the themed background somewhere in its decoration.
    final painted = tester.widgetList<Container>(find.byType(Container)).where((
      c,
    ) {
      final d = c.decoration;
      return d is BoxDecoration && d.color == _hex('#000000');
    });
    expect(painted, isNotEmpty);
    expect(tester.takeException(), isNull);
  });

  testWidgets('syntax highlighting on uses HighlightView for a known language', (
    tester,
  ) async {
    final slide = Slide.create(
      SlideType.code,
    ).copyWith(codeLanguage: 'dart', customMarkdown: 'void main() {}');
    const profile = ThemeProfile(codeHighlightSyntax: true);

    await tester.pumpWidget(_host(slide, profile));
    await tester.pump();

    expect(find.byType(HighlightView), findsOneWidget);
  });

  testWidgets('syntax highlighting off renders monochrome (CRT) text', (
    tester,
  ) async {
    final slide = Slide.create(
      SlideType.code,
    ).copyWith(codeLanguage: 'dart', customMarkdown: 'void main() {}');
    const profile = ThemeProfile(
      codeBackgroundColor: '#000000',
      codeTextColor: '#33FF33',
      codeHighlightSyntax: false,
    );

    await tester.pumpWidget(_host(slide, profile));
    await tester.pump();

    // No per-token highlighting; the code is one flat colour.
    expect(find.byType(HighlightView), findsNothing);
    final codeText = tester.widget<Text>(find.text('void main() {}'));
    expect(codeText.style?.color, _hex('#33FF33'));
    expect(tester.takeException(), isNull);
  });
}