c# – Should Unit Tests share the Same Data set?


We are writing application service tests across our Data Service Class.

Currently writing tests liking add Product, remove Product, check for inventory after sale, etc.
They are all using the same data storage in a list, BeforeEach Method.

When they are all utilizing the same data set, I’m afraid changing one piece of data, will affect all the other unit test. Is that the proper unit test method, or should unit tests have their own data set or factory method?

    product.Add(
        new Product
        {
            ProductId= "1",
            Quantity= 5,
            Code= "Table",
        },
        new Product
        {
            ProductId= "2",
            Quantity= 7,
            Code= "Food",
        }

}