/// <summary>
        /// Asserts that the specification is met.
        /// </summary>
        /// <param name="builder">The specification builder.</param>
        /// <param name="comparer">The event comparer.</param>
        public static void Assert(this IEventCentricAggregateConstructorTestSpecificationBuilder builder,
                                  IEventComparer comparer)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }
            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }
            var specification = builder.Build();
            var runner        = new EventCentricAggregateConstructorTestRunner(comparer);
            var result        = runner.Run(specification);

            if (result.Failed)
            {
                if (result.ButException.HasValue)
                {
                    using (var writer = new StringWriter())
                    {
                        writer.WriteLine("  Expected: {0} event(s),", result.Specification.Thens.Length);
                        writer.WriteLine("  But was:  {0}", result.ButException.Value);

#if NUNIT
                        throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                        throw new Xunit.Sdk.XunitException(writer.ToString());
#endif
                    }
                }
                if (result.ButEvents.HasValue)
                {
                    if (result.ButEvents.Value.Length != result.Specification.Thens.Length)
                    {
                        using (var writer = new StringWriter())
                        {
                            writer.WriteLine("  Expected: {0} event(s) ({1}),",
                                             result.Specification.Thens.Length,
                                             String.Join(",", result.Specification.Thens.Select(_ => _.GetType().Name).ToArray()));
                            writer.WriteLine("  But was:  {0} event(s) ({1})",
                                             result.ButEvents.Value.Length,
                                             String.Join(",", result.ButEvents.Value.Select(_ => _.GetType().Name).ToArray()));

#if NUNIT
                            throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                            throw new Xunit.Sdk.XunitException(writer.ToString());
#endif
                        }
                    }
                    using (var writer = new StringWriter())
                    {
                        writer.WriteLine("  Expected: {0} event(s) ({1}),",
                                         result.Specification.Thens.Length,
                                         String.Join(",", result.Specification.Thens.Select(_ => _.GetType().Name).ToArray()));
                        writer.WriteLine("  But found the following differences:");
                        foreach (var difference in
                                 result.Specification.Thens.
                                 Zip(result.ButEvents.Value,
                                     (expected, actual) => new Tuple <object, object>(expected, actual)).
                                 SelectMany(_ => comparer.Compare(_.Item1, _.Item2)))
                        {
                            writer.WriteLine("    {0}", difference.Message);
                        }

#if NUNIT
                        throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                        throw new Xunit.Sdk.XunitException(writer.ToString());
#endif
                    }
                }
            }
        }
        /// <summary>
        /// Asserts that the specification is met.
        /// </summary>
        /// <param name="builder">The specification builder.</param>
        /// <param name="comparer">The event comparer.</param>
        public static void Assert(this IEventCentricAggregateConstructorTestSpecificationBuilder builder,
            IEventComparer comparer)
        {
            if (builder == null) throw new ArgumentNullException("builder");
            if (comparer == null) throw new ArgumentNullException("comparer");
            var specification = builder.Build();
            var runner = new EventCentricAggregateConstructorTestRunner(comparer);
            var result = runner.Run(specification);
            if (result.Failed)
            {
                if (result.ButException.HasValue)
                {
                    using (var writer = new StringWriter())
                    {
                        writer.WriteLine("  Expected: {0} event(s),", result.Specification.Thens.Length);
                        writer.WriteLine("  But was:  {0}", result.ButException.Value);

#if NUNIT
                        throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                        throw new Xunit.Sdk.AssertException(writer.ToString());
#endif
                    }
                }
                if (result.ButEvents.HasValue)
                {
                    if (result.ButEvents.Value.Length != result.Specification.Thens.Length)
                    {
                        using (var writer = new StringWriter())
                        {
                            writer.WriteLine("  Expected: {0} event(s) ({1}),",
                                result.Specification.Thens.Length,
                                String.Join(",", result.Specification.Thens.Select(_ => _.GetType().Name).ToArray()));
                            writer.WriteLine("  But was:  {0} event(s) ({1})",
                                result.ButEvents.Value.Length,
                                String.Join(",", result.ButEvents.Value.Select(_ => _.GetType().Name).ToArray()));

#if NUNIT
                            throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                            throw new Xunit.Sdk.AssertException(writer.ToString());
#endif
                        }
                    }
                    using (var writer = new StringWriter())
                    {
                        writer.WriteLine("  Expected: {0} event(s) ({1}),",
                            result.Specification.Thens.Length,
                            String.Join(",", result.Specification.Thens.Select(_ => _.GetType().Name).ToArray()));
                        writer.WriteLine("  But found the following differences:");
                        foreach (var difference in
                            result.Specification.Thens.
                                Zip(result.ButEvents.Value,
                                    (expected, actual) => new Tuple<object, object>(expected, actual)).
                                SelectMany(_ => comparer.Compare(_.Item1, _.Item2)))
                        {
                            writer.WriteLine("    {0}", difference.Message);
                        }

#if NUNIT
                        throw new NUnit.Framework.AssertionException(writer.ToString());
#elif XUNIT
                        throw new Xunit.Sdk.AssertException(writer.ToString());
#endif
                    }
                }
            }
        }
 public void SetUp()
 {
     _comparer = new EqualsEventComparer();
     _sut = new EventCentricAggregateConstructorTestRunner(_comparer);
 }
 public void SetUp()
 {
     _comparer = new EqualsEventComparer();
     _sut      = new EventCentricAggregateConstructorTestRunner(_comparer);
 }