How to assert if converter is applied on a type using Fluent Assertions

Question

I need to apply some complex logic for creating map so i have used custom type converter as below:

cfg.CreateMap<ConsumerRequest,IEnumerable<ProviderRequest>>().ConvertUsing<RequestConverter>();

I am using fluentassertions in unit testing and want to assert that ConsumerRequest has RequestConverter applied but not sure how to do it, I think I should be able to right an extension method which will assert the same with some message but not sure how to achieve this, any help will be really appreciated.

Answer 1

Created a extension method on IMapper as below:

public static AutoMapperTypeConverterAssertions<TDestinationModel>ForType<TDestinationModel>(this IMapper subject)
{
  return new AutoMapperTypeConverterAssertions<TDestinationModel>(subject);
}

public class AutoMapperTypeConverterAssertions<TDestinationModel> : ReferenceTypeAssertions<object, AutoMapperTypeConverterAssertions<TDestinationModel>>
{
   public AutoMapperTypeConverterAssertions(object subject)
   {            
     Subject = subject;
   }

   protected override string Context => "auto mapper type converter";

   public AndConstraint<AutoMapperTypeConverterAssertions<TDestinationModel>> ShouldHaveTypeConverterApplied<TSourceModel, TConverterType>(
    string because = "", params object[] becauseArgs)
   {            
      var mapper = Subject as IMapper;
      var foundTypeInConfig = mapper
        .ConfigurationProvider
        .FindTypeMapFor<TSourceModel, TDestinationModel>()
        .TypeConverterType;

      Execute.Assertion
         .BecauseOf(because, becauseArgs)
         .ForCondition(foundTypeInConfig == typeof(TConverterType))
         .FailWith("Expected the mapping for {0} to contain {1} AutoMapper   Type Converter, but was not found.", typeof(TDestinationModel).Name,   typeof(TConverterType).Name);

  }
return new     AndConstraint<AutoMapperTypeConverterAssertions<TDestinationModel>>(this);


}