anchor.diff:  
       final ui.TextStyle ts5 = s5.getTextStyle();
       expect(ts5, equals(ui.TextStyle(fontWeight: FontWeight.w700, fontSize: 12.0, height: 123.0)));
  -    verifyDartUiTextStyleToString(ts5, matches: s5);
  +    expect(ts5, matchesToStringOf(s5));
       final ui.TextStyle ts2 = s2.getTextStyle();
       expect(ts2, equals(ui.TextStyle(color: const Color(0xFF00FF00), fontWeight: FontWeight.w800, fontSize: 10.0, height: 100.0)));
  -    verifyDartUiTextStyleToString(ts2, matches: s2);
  +    expect(ts2, matchesToStringOf(s2));
   
       final ui.ParagraphStyle ps2 = s2.getParagraphStyle(textAlign: TextAlign.center);
       expect(ps2, equals(ui.ParagraphStyle(textAlign: TextAlign.center, fontWeight: FontWeight.w800, fontSize: 10.0, height: 100.0)));
  
positive.code: import 'package:flutter/painting.dart';
  import '../flutter_test_alternative.dart';
  
  void verifyDartUiTextStyleToString(ui.TextStyle textStyle, { required TextStyle matches }) {
      final String description = textStyle.toString();
      expect(description, startsWith('TextStyle('));
      expect(description, endsWith(')'));
  
      expect(description, stringContainsInOrder(<String>[
        if (matches.color != null) 'color: ${matches.color}' else 'unspecified',
        if (matches.decoration != null) 'decoration: ${matches.decoration}' else 'unspecified',
        if (matches.decorationColor != null) 'decorationColor: ${matches.decorationColor}' else 'unspecified',
        if (matches.decorationStyle != null) 'decorationStyle: ${matches.decorationStyle}' else 'unspecified',
        if (matches.decorationThickness != null) 'decorationThickness: ${matches.decorationThickness}' else 'unspecified',
        if (matches.fontWeight != null) 'fontWeight: ${matches.fontWeight}' else 'unspecified',
        if (matches.fontStyle != null) 'fontStyle: ${matches.fontStyle}' else 'unspecified',
        if (matches.textBaseline != null) 'textBaseline: ${matches.textBaseline}' else 'unspecified',
        if (matches.fontFamily != null) 'fontFamily: ${matches.fontFamily}' else 'unspecified',
        if (matches.fontFamilyFallback != null) 'fontFamilyFallback: ${matches.fontFamilyFallback}' else 'unspecified',
        if (matches.fontSize != null) 'fontSize: ${matches.fontSize}' else 'unspecified',
        if (matches.letterSpacing != null) 'letterSpacing: ${matches.letterSpacing}' else 'unspecified',
        if (matches.wordSpacing != null) 'wordSpacing: ${matches.wordSpacing}' else 'unspecified',
        if (matches.height != null) 'height: ${matches.height}' else 'unspecified',
        if (matches.locale != null) 'locale: ${matches.locale}' else 'unspecified',
        if (matches.background != null) 'background: ${matches.background}' else 'unspecified',
        if (matches.foreground != null) 'foreground: ${matches.foreground}' else 'unspecified',
        if (matches.shadows != null) 'shadows: ${matches.shadows}' else 'unspecified',
        if (matches.fontFeatures != null) 'fontFeatures: ${matches.fontFeatures}' else 'unspecified',
      ]));
  }
  
  void main() {
    test('TextStyle control test', () {
  
negative.code:   test('TextStyle using package font', () {
      const TextStyle s6 = TextStyle(fontFamily: 'test');
      expect(s6.fontFamily, 'test');
      expect(s6.getTextStyle(), matchesToStringOf(s6));
  
      const TextStyle s7 = TextStyle(fontFamily: 'test', package: 'p');
      expect(s7.fontFamily, 'packages/p/test');
      expect(s7.getTextStyle(), matchesToStringOf(s7));
  
      const TextStyle s8 = TextStyle(fontFamilyFallback: <String>['test', 'test2'], package: 'p');
      expect(s8.fontFamilyFallback![0], 'packages/p/test');
  