CollectionAssociationTests.cs

namespace EntityFunctors.Tests
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Linq.Expressions;
    using Associations.Impl;
    using EntityFunctors.Associations;
    using EntityFunctors.Extensions;
    using FluentAssertions;
    using Helpers;
    using Mappers;
    using NUnit.Framework;

    [TestFixture]
    public class CollectionAssociationTests
    {
        [Test]
        public void TestMappingCreatesTargetComponent()
        {
            var sut = CreateSut();

            var foo = new Foo
            {
                Bazes = new[] { new Baz(), new Baz() }
            };

            var bar = CreateReader(sut)(foo);
            bar.Should().NotBeNull();
            bar.Names.Should().NotBeNull();
        }

        [Test]
        public void TestMappingAppliesMapper()
        {
            var sut = CreateSut();

            var foo = new Foo
            {
                Bazes = new[] { new Baz { Id = 1 }, new Baz { Id = 2 } }
            };

            var bar = CreateReader(sut)(foo);
            bar.Should().NotBeNull();
            bar.Names.Should().NotBeNull();
            bar.Names.Should().NotBeEmpty();
            bar.Names.Should().BeEquivalentTo(foo.Bazes.Select(_ => _.Id.ToString()));
        }

        [Test]
        public void TestEmptyMapsToEmpty()
        {
            var sut = CreateSut();

            var foo = new Foo
            {
                Bazes = Enumerable.Empty<Baz>()
            };

            var bar = CreateReader(sut)(foo);
            bar.Should().NotBeNull();

            bar.Names.Should().NotBeNull();
            bar.Names.Should().BeEmpty();
        }

        [Test]
        public void TestMappingAssignsDefaultValue()
        {
            var sut = CreateSut();

            var foo = new Foo();

            var bar = CreateReader(sut)(foo);
            bar.Should().NotBeNull();
            bar.Names.Should().BeNull();
        }

        [Test]
        public void TestReverseMappingDoNothing()
        {
            var sut = CreateSut();

            var foo = new Foo();

            var bar = new Bar
            {
                Names = new[] { "a", "b" }
            };

            CreateWriter(sut)(bar, foo);

            foo.Bazes.Should().BeNull();
        }

        private static Func<Foo, Bar> CreateReader(IMappingAssociation association)
        {
            var factory = new MapperFactory(new TestMap(typeof(Foo), typeof(Bar), association));

            return _ => factory.GetReader<Foo, Bar>()(_, null);
        }

        private static Action<Bar, Foo> CreateWriter(IMappingAssociation association)
        {
            var factory = new MapperFactory(new TestMap(typeof(Foo), typeof(Bar), association));

            return (source, target) => factory.GetWriter<Bar, Foo>()(source, target, null);
        }

        private static IMappingAssociation CreateSut()
        {
            Expression<Func<Foo, IEnumerable<Baz>>> source = _ => _.Bazes;

            Expression<Func<Bar, IEnumerable<string>>> target = _ => _.Names;

            return new CollectionAssociation<Foo, Baz, Bar, string>(source, target, _ => _.Id.ToString());
        }
    }
}