Plug-and-play bug example of AutoMapper Explicit Expand feature

ExplicitExpansionWithIncludeBase.cs

using AutoMapper.QueryableExtensions;
using System;
using System.Linq;
using Xunit;

namespace AutoMapper.UnitTests.Bug
{
    public class ExplicitExpansionWithIncludeBase
    {
        /*********** Source Types ***********/
        abstract class EntityBase
        {
            public EntityBase() => Id = Guid.NewGuid();
            public Guid Id { get; set; }
            public User CreatedBy { get; set; }
            public User ModifiedBy { get; set; }
        }

        class User { }
        class Computer : EntityBase { }
        class Script : EntityBase
        {
            public Computer Computer { get; set; }
        }

        /*********** Destination Types ***********/
        class EntityBaseModel
        {
            public Guid Id { get; set; }
            public UserModel CreatedBy { get; set; }
            public UserModel ModifiedBy { get; set; }
        }

        class UserModel { }
        class ComputerModel : EntityBaseModel { }
        class ScriptModel : EntityBaseModel
        {
            public ComputerModel Computer { get; set; }
        }

        private IConfigurationProvider BuildConfiguration()
        {
            return new MapperConfiguration(cfg =>
            {
                cfg.CreateMap<User, UserModel>();
                cfg.CreateMap<EntityBase, EntityBaseModel>()
                .MaxDepth(1)
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
                cfg.CreateMap<Computer, ComputerModel>()
                .MaxDepth(1)
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
                cfg.CreateMap<Script, ScriptModel>()
                .MaxDepth(1)
                .ForMember(d => d.Computer, o => o.ExplicitExpansion())
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
            });
        }

        private Script CreateModel()
        {
            var computer = new Computer()
            {
                CreatedBy = new User(),
                ModifiedBy = new User(),
            };
            return new Script()
            {
                CreatedBy = new User(),
                ModifiedBy = new User(),
                Computer = computer
            };
        }

        [Fact]
        public void ComputerCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand_when_using_expressions()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, c => c.Computer, c => c.CreatedBy).Single(); // Expand Computer and CreatedBy from Script

            // assert
            Assert.Null(scriptModel.Computer.CreatedBy); //Not Explicit call to 'expand'
        }

        [Fact]
        public void ComputerCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer", "CreatedBy").Single(); // Expand Computer and CreatedBy from Script

            // assert
            Assert.Null(scriptModel.Computer.CreatedBy); //CreatedBy from Computer was not specified in 'membersToExpand'
        }

        [Fact]
        public void ComputerCreatedBy_shouldnt_be_null_BUT_ScriptCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer.CreatedBy").Single(); // Expand Computer.CreatedBy from Script

            // assert
            Assert.NotNull(scriptModel.Computer.CreatedBy);
            Assert.Null(scriptModel.CreatedBy); //CreatedBy from Script was not specified in 'membersToExpand'
        }

        [Fact]
        public void ScriptCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer.CreatedBy").Single(); // Expand Computer.CreatedBy from Script

            // assert
            Assert.Null(scriptModel.CreatedBy); //CreatedBy from Script was not specified in 'membersToExpand'
        }
    }

    public class ExplicitExpansionWithIncludeBaseUsingNewKeyword
    {
        /*********** Source Types ***********/
        abstract class EntityBase
        {
            public EntityBase() => Id = Guid.NewGuid();
            public Guid Id { get; set; }
            public User CreatedBy { get; set; }
            public User ModifiedBy { get; set; }
        }

        class User { }
        class Computer : EntityBase { }
        class Script : EntityBase
        {
            public Computer Computer { get; set; }
        }

        /*********** Destination Types ***********/
        class EntityBaseModel
        {
            public Guid Id { get; set; }
            public UserModel CreatedBy { get; set; }
            public UserModel ModifiedBy { get; set; }
        }

        class UserModel { }
        class ComputerModel : EntityBaseModel
        {
            public new UserModel CreatedBy { get; set; } //NOTE: the 'new' keyword here make the tests pass
        }
        class ScriptModel : EntityBaseModel
        {
            public new UserModel CreatedBy { get; set; } //NOTE: the 'new' keyword here make the tests pass
            public ComputerModel Computer { get; set; }
        }

        private IConfigurationProvider BuildConfiguration()
        {
            return new MapperConfiguration(cfg =>
            {
                cfg.CreateMap<User, UserModel>();
                cfg.CreateMap<EntityBase, EntityBaseModel>()
                .MaxDepth(1)
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
                cfg.CreateMap<Computer, ComputerModel>()
                .MaxDepth(1)
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
                cfg.CreateMap<Script, ScriptModel>()
                .MaxDepth(1)
                .ForMember(d => d.Computer, o => o.ExplicitExpansion())
                .ForMember(d => d.ModifiedBy, o => o.ExplicitExpansion())
                .ForMember(d => d.CreatedBy, o => o.ExplicitExpansion());
            });
        }

        private Script CreateModel()
        {
            var computer = new Computer()
            {
                CreatedBy = new User(),
                ModifiedBy = new User(),
            };
            return new Script()
            {
                CreatedBy = new User(),
                ModifiedBy = new User(),
                Computer = computer
            };
        }

        [Fact]
        public void ComputerCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand_when_using_expressions()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, c => c.Computer, c => c.CreatedBy).Single(); // Expand Computer and CreatedBy from Script

            // assert
            Assert.Null(scriptModel.Computer.CreatedBy); //Not Explicit call to 'expand'
        }

        [Fact]
        public void ComputerCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer", "CreatedBy").Single(); // Expand Computer and CreatedBy from Script

            // assert
            Assert.Null(scriptModel.Computer.CreatedBy); //CreatedBy from Computer was not specified in 'membersToExpand'
        }

        [Fact]
        public void ComputerCreatedBy_shouldnt_be_null_BUT_ScriptCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer.CreatedBy").Single(); // Expand Computer.CreatedBy from Script

            // assert
            Assert.NotNull(scriptModel.Computer.CreatedBy);
            Assert.Null(scriptModel.CreatedBy); //CreatedBy from Script was not specified in 'membersToExpand'
        }

        [Fact]
        public void ScriptCreatedBy_should_be_null_because_it_was_not_specified_in_members_to_expand()
        {
            // arrange
            var config = BuildConfiguration();
            var script = CreateModel();

            // act
            var scriptModel = new[] { script }.AsQueryable()
                .ProjectTo<ScriptModel>(config, null, "Computer.CreatedBy").Single(); // Expand Computer.CreatedBy from Script

            // assert
            Assert.Null(scriptModel.CreatedBy); //CreatedBy from Script was not specified in 'membersToExpand'
        }
    }
}