public void CustomFormatter_Must_Be_Applied(string message, LogLevel logLevel)
{
Func <LogLevel, object, Exception, string> customFormatter
= (level, state, ex) => level + "hello world" + state.ToString();
Func <string, LogLevel, bool> filter = (categoryName, level) => true;
var coreLogger = new FakeCoreLogger();
var logger = new AWSLogger("TestCategory", coreLogger, filter, customFormatter);
logger.Log(logLevel, 0, message, null, (state, ex) => state.ToString());
string expectedMessage = customFormatter(logLevel, message, null);
Assert.Equal(expectedMessage, coreLogger.ReceivedMessages.First());
}