ConcurrentDictionary

Hi, When I use autofixture to generate a Dictionary<T, U> I get values populated in it by default, but with a ConcurrentDictionary<T, U> I don’t.

Is this by design & I should use a specimen builder to alter that behaviour myself, or is it a missing feature or bug?

[Ergamon]

Hello, I cannot tell the reasons behind this, but it looking at the source code the supported collections are hard coded. So it is not something like “does type implement IDictionary”, it is “is type Dictionary<,>”. Therefore ConcurrentDictionary does not work. You dont need to create your own specimenbuilder, you can use what is already there:

      var fixture = new Fixture();

      var query = new ModestConstructorQuery();
      var methodInvoker = new MethodInvoker(query);
      var dictionaryFiller = new DictionaryFiller();
      var postProcessor = new Postprocessor(methodInvoker, dictionaryFiller);
      var exactTypeSpecification = new ExactTypeSpecification(typeof(ConcurrentDictionary<,>));
      var specimenBuilder = new FilteringSpecimenBuilder(postProcessor, exactTypeSpecification);

      fixture.Customizations.Add(specimenBuilder);

[Ergamon]

Just that I dont spread wrong information, it is is not only Dictionary<,>. I just wanted to point out that the list of types can be found directly in Fixture.cs. E.g. it is also SortedDictionary<,>, but as you already figured out, it is not ConcurrentDictionary<,>. By all means I would say that a future implementation should check for the interface.