Blog.WorkOnDataTestFixture.cs

[Fact]
public void Delete_WithMessageId_ShouldDeleteMessage()
{
    // Arrange
    Message[] leftOverMessages = CreateMessages();
    Message targetMessage = CreateMessage();
    var repo = new InMemoryMessageRepository(leftOverMessages.Append(targetMessage));
    var service = CreateMessageService(repo);

    // Act
    DeleteResult result = service.DeleteMessageById(targetMessage.Id);

    // Assert
    Assert.Equal(DeleteResult.Deleted, result);
    Assert.Equal(targetMessage.Id, result.Value);

    Message[] actual = repo.GetMessages();
    Assert.DoesNotContain(targetMessage, actual);
    Assert.All(leftOverMessages, msg => Assert.Contains(msg, actual));
}