public class CustomAssertionStrategy : IAssertionStrategy
    {
        private readonly List<string> failureMessages = new List<string>();

        /// <summary>
        /// Returns the messages for the assertion failures that happened until now.
        /// </summary>
        public IEnumerable<string> FailureMessages => failureMessages;

        /// <summary>
        /// Discards and returns the failure messages that happened up to now.
        /// </summary>
        public IEnumerable<string> DiscardFailures()
        {
            var discardedFailures = failureMessages.ToArray();
            failureMessages.Clear();
            return discardedFailures;
        }

        /// <summary>
        /// Will throw a combined exception for any failures have been collected since <see cref="StartCollecting"/> was called.
        /// </summary>
        public void ThrowIfAny(IDictionary<string, object> context)
        {
            if (failureMessages.Any())
            {
                var builder = new StringBuilder();
                builder.AppendLine(string.Join(Environment.NewLine, failureMessages));

                if (context.Any())
                {
                    foreach (KeyValuePair<string, object> pair in context)
                    {
                        builder.AppendFormat("\nWith {0}:\n{1}", pair.Key, pair.Value);
                    }
                }

                Services.ThrowException(builder.ToString());
            }
        }

        /// <summary>
        /// Instructs the strategy to handle a assertion failure.
        /// </summary>
        public void HandleFailure(string message)
        {
            failureMessages.Add(message);
        }
    }

using (var scope = new AssertionScope(new CustomAssertionStrategy()))
            {

                false.Should().BeTrue();
                true.Should().BeFalse();
            }