An extension method to flatten Exceptions with InnerExceptions

ExceptionExtensions.cs

public static class ExceptionExtensions
    {
        public static IEnumerable<Exception> FlattenHierarchy(this Exception ex)
        {
            if (ex == null)
            {
                throw new ArgumentNullException("ex");
            }

            var innerException = ex;
            do
            {
                yield return innerException;
                innerException = innerException.InnerException;
            }
            while (innerException != null);
        }
    }

ExceptionExtensionsTests.cs

[TestFixture]
    public class ExceptionExtensionsTests
    {
        [Test]
        public void GetInnerExceptionMessage()
        {
            const string test = "This is the base exception This is the inner exception";
            var message = string.Empty;
            
            try
            {
                var innerException = new Exception("This is the inner exception");
                throw new Exception("This is the base exception",innerException);
            }
            catch (Exception exception)
            {
                var list = exception.FlattenHierarchy();
                foreach (var exception1 in list)
                {
                    message = string.Concat(message, exception1.Message);
                    message = string.Concat(message, " ");
                }
            }
            finally
            {
                Assert.IsTrue(!string.IsNullOrWhiteSpace(message));
                Assert.IsTrue(test == message.Trim());
            }
        }
    }