Question

I am currently using Unity with MOQ to do my unit testing for WCF. In the application’s code, I have the following:

private void MyMethod()
{
.....
.....
    _proxy = new UnityContainer().LoadConfiguration().Resolve<IMyInterface>();
.....
}

In the application’s app.config, I have the following:

<container>
  <register type="IMyInterface" mapTo="MyActualObject" />
</container> 

In the unit test’s app.config, I replace that with my mock object implementation of the proxy.

<container>
  <register type="IMyInterface" mapTo="MyMockObject" />
</container> 

That is all working fine. But what I would like to do further is for certain tests, I would like to replace MyMockObject with a different mock object implementation.

Is it possible to change the registered type at runtime? I have tried modifying the application config during runtime but it fails to detect the change.

 Configuration appConfig = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
 var section = (UnityConfigurationSection)appConfig.GetSection("unity");
 section.Containers[0].Registrations[0].MapToName = "AnotherMockObject";
 appConfig.Save();  

Thanks!!

Answer 1

Yes its possible.

You can configure Unity as many times as you want. If there’s a conflict the most recent definition wins.

In your case if you want to make a runtime change, use the fluent API instead of the config file. Try something like this:

IUnityContainer container = new UnityContainer();
container.LoadConfiguration();
container.RegisterType<IMyInterface, AnotherMockObject>();

// use AnotherMockObject
_proxy = Resolve<IMyInterface>();

The documentation for Registering Types and Type Mappings