anchor.diff:      expect(material.elevation, 0.0);
       expect(material.shadowColor, null);
       expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(2.0)));
  -    expect(material.textStyle?.color, const Color(0x61000000));
  -    expect(material.textStyle?.fontFamily, 'Roboto');
  -    expect(material.textStyle?.fontSize, 14);
  -    expect(material.textStyle?.fontWeight, FontWeight.w500);
  +    expect(material.textStyle!.color, const Color(0x61000000));
  +    expect(material.textStyle!.fontFamily, 'Roboto');
  +    expect(material.textStyle!.fontSize, 14);
  +    expect(material.textStyle!.fontWeight, FontWeight.w500);
       expect(material.type, MaterialType.transparency);
     });
   
  
positive.code:     expect(material.elevation, 0.0);
      expect(material.shadowColor, null);
      expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(2.0)));
      expect(material.textStyle?.color, const Color(0xdd000000));
      expect(material.textStyle?.fontFamily, 'Roboto');
      expect(material.textStyle?.fontSize, 14);
      expect(material.textStyle?.fontWeight, FontWeight.w500);
      expect(material.type, MaterialType.transparency);
  
      final Offset center = tester.getCenter(find.byType(FlatButton));
  
negative.code:     expect(material.elevation, 0.0);
      expect(material.shadowColor, null);
      expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(2.0)));
      expect(material.textStyle!.color, const Color(0xdd000000));
      expect(material.textStyle!.fontFamily, 'Roboto');
      expect(material.textStyle!.fontSize, 14);
      expect(material.textStyle!.fontWeight, FontWeight.w500);
      expect(material.type, MaterialType.transparency);
  
      // Disabled FlatButton
  