Help wrtiting test for models that use CSV data

Hi, could use some help with this.

I have an app that imports CSV data (which it receives from another
app as an automated entry to a data field on a form)

I want to write test for the models that use this data. I have one
model with no database that takes the CSV record and makes it an
object that I can work with.

Then that object gets split into Customer, Order and LineItem models.

This means that I need CSV raw data to build the tests around. My
main question is where do I put this data and how do I store it. I
could build some test strings, or I could use test files, but it would
be nice to make them accessible to different model tests.

I am still green at writing tests and cant get my head around how best
to go about this.

Any ideas??