Improving LINQ Code Reusability: Select Method

namespace Tests
{
	using System;

	using NUnit.Framework;

	using Domain;
	using DataContracts;
	using Mapper;


	[TestFixture]
	public class ObjectMapperTests
	{
		[Test]
		public void Given_a_non_existing_mapping_when_mapping_object_then_should_throw_InvalidOperationException()
		{
			// arrange
			IObjectMapper mapper = new ObjectMapper();
			var albumDetail = new AlbumDetail();

			// act/assert
			Assert.Throws<InvalidOperationException>(() => 
				// non-existing mapping
				mapper.Map<AlbumDetail, AlbumSummary>(albumDetail)
			);
		}

		[Test, TestCaseSource("AlbumSummaryTestCases")]
		public void Given_an_album_when_mapping_to_album_summary_should_equals_expected_album_summary(Album album, AlbumSummary expectedAlbumSummary)
		{
			// arrange
			IObjectMapper mapper = new ObjectMapper();

			// act
			AlbumSummary albumSummary = mapper.Map<Album, AlbumSummary>(album);

			// assert
			Assert.AreEqual(albumSummary, expectedAlbumSummary);
		}


		[Test, TestCaseSource("AlbumDetailTestCases")]
		public void Given_an_album_when_mapping_to_album_detail_should_equals_expected_album_detail(Album album, AlbumDetail expectedAlbumDetail)
		{
			// arrange
			IObjectMapper mapper = new ObjectMapper();

			// act
			AlbumDetail albumDetail = mapper.Map<Album, AlbumDetail>(album);

			// assert
			Assert.AreEqual(albumDetail, expectedAlbumDetail);
		}

		#region Test cases

		private static object[] AlbumDetailTestCases = 
		{
			new object[] {
			    null,
			    null
			},

			new object[] {
			    new Album(),
			    new AlbumDetail()
			}

			// TO-DO: Add more test cases
		};


		private static object[] AlbumSummaryTestCases = 
		{
			new object[] {
			    null,
			    null
			},

			new object[] {
			    new Album(),
			    new AlbumSummary()
			},


			new object[] {
				new Album {
					AlbumId = 1,
					Price = 10.0m,
					Title = "The Dreamer",

					Artist = new Artist {
						ArtistId = 1,
						Name = "José James"
					},

					Genre = new Genre {
						GenreId = 1,
						Name = "Jazz"
					}
				},

				// expected mapped object
				new AlbumSummary{
					AlbumId = 1,
					ArtistName = "José James",
					Title = "The Dreamer"
				}
			},


			new object[] {
				new Album {
					AlbumId = 2,
					Price = 12.0m,
					Title = "Final Conversation of Kings",

					Artist = new Artist {
						ArtistId = 2,
						Name = "The Butterfly Effect"
					},

					Genre = new Genre {
						GenreId = 2,
						Name = "Progressive Rock"
					}
				},

				// expected mapped object
				new AlbumSummary {
					AlbumId = 2,
					ArtistName = "The Butterfly Effect",
					Title = "Final Conversation of Kings"
				}
			},

			
			new object[] {
				new Album {
					AlbumId = 4,
					Price = 10.0m,
					Title = "Heritage",

					Artist = new Artist {
						ArtistId = 4,
						Name = "Opeth"
					},

					Genre = new Genre {
						GenreId = 4,
						Name = "Metal"
					}
				},

				// expected mapped object
				new AlbumSummary {
					AlbumId = 4,
					ArtistName = "Opeth",
					Title = "Heritage"
				}
			}
		};

		#endregion
	}
}