mixbox_flutter/test/mixbox_loader_test.dart

import 'dart:io';
import 'dart:convert';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mixbox/mixbox.dart';
import 'package:mixbox/mixbox_loader.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  group('MixboxLoader', () {
    test('initializeFromAsset loads and decompress LUT', () async {
      // Read the actual LUT file from the assets directory for mocking
      // In a real environment, we'd use the relative path from the project root
      final lutFile = File('assets/mixbox_lut.dat');
      if (!lutFile.existsSync()) {
        fail('LUT file not found at ${lutFile.absolute.path}. Run tests from project root.');
      }
      final lutBytes = await lutFile.readAsBytes();

      // Mock rootBundle
      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMessageHandler('flutter/assets', (
        ByteData? message,
      ) async {
        // The message contains the asset key encoded as UTF-8
        final key = utf8.decode(message!.buffer.asUint8List());
        if (key.contains('mixbox_lut.dat')) {
          return ByteData.view(lutBytes.buffer);
        }
        return null;
      });

      // Call initializeFromAsset
      await MixboxLoader.initializeFromAsset('assets/mixbox_lut.dat');

      expect(Mixbox.isInitialized, isTrue);

      // Verify basic color mixing
      // Blue: 0, 0, 255 -> 0xFF0000FF
      // Yellow: 255, 255, 0 -> 0xFFFFFF00
      const blue = 0xFF0000FF;
      const yellow = 0xFFFFFF00;

      final mixed = Mixbox.lerp(blue, yellow, 0.5);

      final r = (mixed >> 16) & 0xFF;
      final g = (mixed >> 8) & 0xFF;
      final b = mixed & 0xFF;

      // In Mixbox, blue + yellow = green
      // (Standard lerp would give gray/brown: 127, 127, 127)
      expect(g, greaterThan(r), reason: 'Mixed color should be greenish (high Green)');
      expect(g, greaterThan(b), reason: 'Mixed color should be greenish (high Green)');
      expect(r, lessThanOrEqualTo(100), reason: 'Red should be relatively low in green');
      expect(b, lessThanOrEqualTo(100), reason: 'Blue should be relatively low in green');
    });

    test('generateTestLut creates a valid sized LUT', () {
      final lut = MixboxLoader.generateTestLut();
      // Expected size: 64 * 64 * 64 * 3 + 4353 = 790785
      expect(lut.length, equals(790785));
    });
  });

  group('MixboxColorExtension', () {
    test('toMixboxInt and fromMixboxInt', () {
      const color = Color(0xFF123456);
      expect(color.toMixboxInt(), equals(0xFF123456));
    });

    test('mixWith', () {
      // This test depends on Mixbox being initialized
      // If the first test passed, it is.
      if (Mixbox.isInitialized) {
        const blue = Color(0xFF0000FF);
        const yellow = Color(0xFFFFFF00);
        final green = blue.mixWith(yellow, 0.5);

        expect(green.green, greaterThan(green.red));
        expect(green.green, greaterThan(green.blue));
      }
    });
  });
}