public void AddEntitiesByTypeAreMapped() {
            var mockMapper = SetupPostAndUserMaps();
            var target = new CustomConfigurationWithAddEnumerable(mockMapper.Object);

            Assert.NotNull(target);
            Assert.Equal(2, target.Maps.Count());
            Assert.Equal(1, target.Maps.Count(m => m.Type == typeof(Post)));
            Assert.Equal(1, target.Maps.Count(m => m.Type == typeof(User)));
            mockMapper.Verify();
        }