Attaching Fixture Files in Rails Model Tests

If you want to attach fixture files in a model test. Assuming your ActiveStorage association is already set up, if it's not set up, check this out, then follow these steps:

1. Make sure your desired fixture file has been placed in your test/fixtures/files folder
2. Attach the fixture to the model instance by providing the .attach method with a hash including an IO object and the name of the file you wish to attach.

It should look something like this:

@object.image.attach(io: File.open('test/fixtures/files/filename'), filename: 'filename')