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c#dynamicxunitfluent-assertions

Cannot read dynamic properties with FluentAssertions

I am using XUnit and fluentassertions in c sharp for my unit tests. Below is where I get a dynamic type, convert a dynamic object to that dynamic type and try to do an assertion:

        var dynamicType = Type.GetType(...);

        dynamic? myObject = JsonSerializer.Deserialize(myJSONData, dynamicType);

        myObject!.Products!.Should().NotBeNull();

If I debug it, myObject does have the required properties and values, however c sharp and fluentassertion throw this error:

  Microsoft.CSharp.RuntimeBinder.RuntimeBinderException : 'xxxxx.Products' does not contain a definition for 'Should'

Is it possible to do the comparison or did I miss out anything?

Solution

  • It's a limitation in .NET. It does not support extension methods for dynamic objects.

    A workaround is to cast myObject into an object, such that the appropriate overload of Should can be determined at compile time.

    Some related issues: