Allowing Appended Items Without Failing Verification but Failing on Existing Item Changes

[JoaBjo]

Hi,

I'm using Verify to test an API that returns a list of objects. I want to monitor changes in the returned objects over time. Specifically, I would like the verification to:

Pass (and possibly auto-verify) when new items are appended to the list.
Fail when existing items are modified.
In other words, I want to allow the list to grow with new items without causing the test to fail, but I want to detect any changes to items that were already verified.

Is there a way to achieve this behavior with Verify?

Here is a simple example to illustrate the scenario:

• First Run (CreateExamplesA): The original list is verified.
• Second Run (CreateExamplesB): A new item is appended to the list. Ideally, this should not cause the test to fail and could be auto-verified.
• Third Run (CreateExamplesC): An existing item's Name property is changed. This should cause the verification to fail.

namespace SnapshotTests
{
    public class Example
    {
        [Fact]
        public Task Example_Test()
        {
            return Verify(Item.CreateExamplesA()); // Initial verification with the original list
            //return Verify(Item.CreateExamplesB()); // New item appended; should pass and possibly auto-verify
            //return Verify(Item.CreateExamplesC()); // Existing item modified; should fail verification
        }
    }

    public class Item
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Type { get; set; }

        public static List<Item> CreateExamplesA()
        {
            return new List<Item>
            {
                new Item { Id = 1, Name = "Laptop", Type = "Electronics" },
                new Item { Id = 2, Name = "Desk Chair", Type = "Furniture" },
                new Item { Id = 3, Name = "Notebook", Type = "Stationery" },
                new Item { Id = 4, Name = "Headphones", Type = "Electronics" },
                new Item { Id = 5, Name = "Lamp", Type = "Furniture" }
            };
        }

        public static List<Item> CreateExamplesB()
        {
            return new List<Item>
            {
                new Item { Id = 1, Name = "Laptop", Type = "Electronics" },
                new Item { Id = 2, Name = "Desk Chair", Type = "Furniture" },
                new Item { Id = 3, Name = "Notebook", Type = "Stationery" },
                new Item { Id = 4, Name = "Headphones", Type = "Electronics" },
                new Item { Id = 5, Name = "Lamp", Type = "Furniture" },
                // New item appended
                new Item { Id = 6, Name = "Mouse", Type = "Electronics" }
            };
        }

        public static List<Item> CreateExamplesC()
        {
            return new List<Item>
            {
                new Item { Id = 1, Name = "Laptop", Type = "Electronics" },
                // Existing item modified (Name changed from "Desk Chair" to "DeskChair")
                new Item { Id = 2, Name = "DeskChair", Type = "Furniture" },
                new Item { Id = 3, Name = "Notebook", Type = "Stationery" },
                new Item { Id = 4, Name = "Headphones", Type = "Electronics" },
                new Item { Id = 5, Name = "Lamp", Type = "Furniture" }
            };
        }
    }
}

[SimonCropp]

no this is not possible.

Verify attempts to mitigate this by making the "accept changes" process. eg you can do it with a keyboard shortcut https://github.com/VerifyTests/DiffEngine/blob/main/docs/tray.md#accept-all-hotkey

[JoaBjo]

Thanks Simon