Update readme for C3D.Extensions.Logging.Xunit

Author: CZEMacLeod

src/C3D/Extensions/Logging/Xunit/README.md

@@ -42,4 +42,38 @@ Alternatively, you can explicitly add the output, and/or setup the logging confi
 logging
 	.AddXunit(output, config=>{
 	});
-```
+```
+
+### Direct injection
+
+```c#
+private readonly ITestOutputHelper output;
+
+ILogger<ClassUnderTest> log = output.CreateLogger<ClassUnderTest>();
+
+\\ Assuming that the constuctor of ClassUnderTest takes an ILogger or ILogger<ClassUnderTest>
+var sut = new ClassUnderTest(log);
+
+\\ perform tests with logging...
+```
+
+Here the ILogger creation line might replace something like 
+```c#
+ILogger<ClassUnderTest> log = Microsoft.Extensions.Logging.Abstractions.NullLoggerFactory.Instance.CreateLogger<ClassUnderTest>();
+```
+
+### Factory
+
+You can also create a LoggerFactory if you need to using something like
+
+```c#
+private readonly ITestOutputHelper output;
+
+var loggerFactory = LoggerFactory.Create(builder => builder.AddXunit(output));
+```
+
+### Fixtures
+
+The same mechanisms used in tests based on injecting `ITestOutputHelper` into the test class, can be used in fixtures.
+However, in fixtures you inject `IMessageSink`. The same extension methods are available for both interfaces.
+

src/C3D/Extensions/Logging/Xunit/XunitLoggerProvider.cs

@@ -54,7 +54,7 @@ public ILogger CreateLogger(string categoryName) =>
             name => output1 is null ? 
                     (output2 is null ? NullLogger.Instance : 
                      new MessageSinkLogger(name, output2, GetOptions)) :
-                    new TextOutputLogger(name, output1, GetOptions));
+                     new TextOutputLogger(name, output1, GetOptions));
 
     private void Dispose(bool disposing)
     {