Substiture for ILoggerFactory.CreateLogger<T>

[alvipeo]

In almost any .NET project I need to have a substitute for ILoggerFactory and its probably most used method CreateLogger<T>(). It returns ILogger<T>, which is in turn:

public interface ILogger<out TCategoryName> : Microsoft.Extensions.Logging.ILogger

Any idea how could this be substituted?

[olegd-superoffice]

@alvipeo CreateLogger<T>() is an extension method so you need to substitute CreateLogger(string) (which is called from extension) instead:

var loggerFactory = Substitute.For<ILoggerFactory>();
loggerFactory.CreateLogger(null).ReturnsForAnyArgs(NullLogger<MyType>.Instance);

Or maybe just use NullLoggerFactory instead of mocking.

[dtchepak]

In addition to @olegd-superoffice's suggestion on returning a substitute/NullLogger, there are some changes in #732 that may help with checking ILogger calls.

[304NotModified]

related: https://github.com/nsubstitute/NSubstitute/issues/597

[olegd-superoffice]

@alvipeo Could you please close this issue if your question was answered?

[304NotModified]

I think the question has been answered and therefore I will close this one.

Please let us know if you need further information or would like us to take another look at this