I recently upgraded Visual Studio 2019, and I was puzzled as all tests which were using SkiaSharp would crash with a BadImagFormatException:

System.TypeInitializationException : The type initializer for 'SkiaSharp.SKImageInfo' threw an exception.
    ---- System.BadImageFormatException : An attempt was made to load a program with an incorrect format.

My build settings were all set to Any CPU and I did not tick the checkbox Prefer 32-bit. I somehow suspected that the tests were given an x86 library, so I tried adding following to the *.csproj file:

<ShouldIncludeNativeSkiaSharp>True</ShouldIncludeNativeSkiaSharp>
<PreferredNativeSkiaSharp>x64</PreferredNativeSkiaSharp>

as suggested in this SkiaSharp issue on the topic. It did not help.

Select the correct CPU architecture for your Visual Studio Tests

Microsoft’s article on running tests as a 64-bit process pointed me to the correct solution. Somehow, the default setting I was using for the processor architecture, when running my tests, changed after updating Visual Studio.

Setting the Processor Architecture for AnyCPU Projects back to Auto solved the issue.