Tests for old .NET Frameworks

[MPrtenjak]

Type of issue

[ ] Bug
[X] Question (e.g. about handling/usage)
[ ] Request for new feature/improvement

Expected Behavior

Why are tests for .NET 3.5 different than for the other platforms? I am asking that because tests are failing.

For instance, this test:

        public void can_create_standard_qrcode_graphic()
        {
            var gen = new QRCodeGenerator();
            var data = gen.CreateQrCode("This is a quick test! 123#?", QRCodeGenerator.ECCLevel.H);
            var bmp = new ArtQRCode(data).GetGraphic(10);

            var result = HelperFunctions.BitmapToHash(bmp);
#if NET35_OR_GREATER || NET40_OR_GREATER
            result.ShouldBe("11ebdda91b9632d016798cb6de2f5339");
#else
            result.ShouldBe("cb38c3156eaf13cdfba699bdafc3a84c");
#endif
        }

Even though I am running tests in .NET 3.5 the result is equal to "cb38c3156eaf13cdfba699bdafc3a84c", which sounds to me as correct.
Why would a result of a function depend on the .NET version?

Your Environment

I am using Visual Studio 2022. Just download from GitHub, open in VS 2022, and run tests.

Some test fails on .NET 3.5 and .NET 4.5

Thanks

[codebude]

Then there's maybe a change in the .NET Framework implementation...

Background:
The idea of the tests was to generate a PNG (because in opposite to JPEG it has lossless compression and the same input Image object should return the same PNG file/bytes every time) and build a hash of the resulting file. Thus it should be ensured, that the QRCode has to look exactly the same to make an positive assumption.

When I wrote the tests the same Image object, saved to PNG file, created byte-wise different files, when running in .NET 3.5/.NET 4.X vs all other framework versions. Back then I checked the files in a hex editor and saw that the PNG headers, written bei .NET differed in dependency to the used framework version.
Different PNG file headers resulted in different checksums. That's why I added the compiler flags/branches in the test case.

If it returns the same checksum now, then there must have been a patch in the framework.

[MPrtenjak]

Thanks, that is exactly what I thought.

Well, because I had to download .NET Framework 4.5 additionaly, maybe there is something wrong on my side.

Thanks for the answer and have a great day.