ConsumersTestHarness.cs

using Decorators;
using MessageObservers;
using System;
using System.Collections.Generic;

public class ConsumersTestHarness
{
    readonly BusTestHarness _testHarness;
    readonly IList<Action<IReceiveEndpointConfigurator>> _consumerConfigurations;

    public ConsumersTestHarness(BusTestHarness testHarness, string queueName)
    {
        _testHarness = testHarness;
        _consumerConfigurations = new List<Action<IReceiveEndpointConfigurator>>();

        if (string.IsNullOrWhiteSpace(queueName))
            testHarness.OnConfigureReceiveEndpoint += ConfigureReceiveEndpoint;
        else
            testHarness.OnConfigureBus += configurator => ConfigureNamedReceiveEndpoint(configurator, queueName);
    }

    public ReceivedMessageList Add<TConsumer>(IConsumerFactory<TConsumer> consumerFactory)
        where TConsumer : class, IConsumer
    {
        var consumed = new ReceivedMessageList(_testHarness.TestTimeout);

        var decorator = new TestConsumerFactoryDecorator<TConsumer>(consumerFactory, consumed);

        _consumerConfigurations.Add(cfg => cfg.Consumer(decorator));

        return consumed;
    }

    protected virtual void ConfigureReceiveEndpoint(IReceiveEndpointConfigurator configurator)
    {
        foreach (var cfg in _consumerConfigurations)
        {
            cfg(configurator);
        }
    }

    protected virtual void ConfigureNamedReceiveEndpoint(IBusFactoryConfigurator configurator, string queueName)
    {
        configurator.ReceiveEndpoint(queueName, x =>
        {
            foreach (var cfg in _consumerConfigurations)
            {
                cfg(x);
            }
        });
    }
}