Unit-testing Prism with Service Locator?

Question

I am building a Prism 4 app, and I use the ServiceLocator to instantiate objects. The ServiceLocator is causing unit testing problems, and that leads me to wonder whether I should go back to injecting the IoC container into each class that needs it.

Here is an example of the problem from a repository base class:

protected RepositoryBase(string filePath, Type contextType, string edmName)
{
    m_Logger = ServiceLocator.Current.GetInstance<ILoggerFacade>();

    // Log invocation
    m_Logger.Log("RepositoryBase constructor invoked.", Category.Info, Priority.None);

    // Create object context
    ...

    // Log completion
    m_Logger.Log("RepositoryBase constructor completed.", Category.Info, Priority.None);
}

I am creating unit tests for my repository, and I have discovered that the ServiceLocator doesn't work, presumably because Prism isn't initialized for my test.

Can the ServiceLocator be used in a testing context? Sould I drop it and go back to injecting the IoC container directly? Since service locators seem to be falling out of favor generally, would I be better off not using it? Thanks for your help.

Answer 1

You need to create a mock IServiceLocator, initialize the service locator with your mock provider in your test.

That should do it.