public async Task Update_Book_Language()
{
var book = await BookHelpers.CreateValidBook();
var repository = new BookRepository(_fixture.Context);
(await repository.ExistsAsync(book.Id)).Should().BeTrue();
var sut = await repository.LoadAsync(book.Id);
var bookId = sut.Id;
sut.Should().NotBeNull();
sut.Language.Should().BeNull();
var language = await LanguageHelpers.CreateValidLanguage();
await BookHelpers.UpdateLanguage(sut.Id, language);
sut = await repository.LoadAsync(book.Id);
await _fixture.Context.Entry(sut).ReloadAsync();
sut.Language.Id.Should().Be(language.Id);
sut.Language.Name.Should().Be(language.Name);
sut.Id.Should().Be(bookId);
}