public void AddCommandHandler_can_handle_type_handling_multiple_commands(IServiceCollection services)
        {
            ServiceCollectionExtensions.AddCommandHandler(services, typeof(MixedTestCommandHandler));

            Mock.Get(services).Verify(p => p.Add(It.Is <ServiceDescriptor>(sd => sd.ServiceType == typeof(ICommandHandler <FirstTestCommand>) && sd.ImplementationType == typeof(MixedTestCommandHandler))));

            Mock.Get(services).Verify(p => p.Add(It.Is <ServiceDescriptor>(sd => sd.ServiceType == typeof(ICommandHandler <SecondTestCommand>) && sd.ImplementationType == typeof(MixedTestCommandHandler))));
        }
        public void AddCommandHandler_registers_handler_by_its_type_generic_syntax(IServiceCollection services)
        {
            ServiceCollectionExtensions.AddCommandHandler <FirstTestCommandHandler>(services);

            Mock.Get(services).Verify(p => p.Add(It.Is <ServiceDescriptor>(sd => sd.ServiceType == typeof(ICommandHandler <FirstTestCommand>) && sd.ImplementationType == typeof(FirstTestCommandHandler))));
        }