I'm writing some unit tests for my View Model class. The constructor of this class is injected with an ILoggerService. This interface defines 1 method GetLog which returns an ILogger. Something like below where this represents a class that implements ILoggable:-
protected ViewModelBase(ILoggerService loggerService)
{
Logger = loggerService.GetLog(this);
}
I'm trying to unit test my CreateNewOrder method that looks like below:
private void CreateNewOrder(INewOrderViewModel newOrderViewModel)
{
Logger.Log("Sending Create New Order Message", LogCategory.Info);
var createNewOrderMessage = new OrderMessage(newOrderViewModel);
_eventAggregator.GetEvent<CreateOrderEvent>().Publish(createNewOrderMessage);
}
How would I go about Mocking the ILoggerService so that a valid Logger is returned? At the moment my Unit test throws a NullReferenceExeception.
I'm using Moq to do my mocking.
I'm imagining I need to do something along the lines of
var loggerService = new Mock<ILoggerService>();
loggerService.Setup(svc => svc.GetLog(??))
But I can't see how without making my test class implement ILoggable.
Thanks in advance.
I'm not sure what the type is of the GetLog
method parameter, but I assume it's something like object
so the logger service can determine the type requesting a logger. You can use It
to mock parameters in a method you are setting up, as seen below.
var logger = new Mock<ILogger>();
var loggerService = new Mock<ILoggerService>();
loggerService.Setup(c => c.GetLog(It.IsAny<object>())
.Returns(logger.Object);
Then pass logger.Object
to whatever method or type needs an ILoggerService
.